JavaScript Programs for Beginners

1. Find the Largest of Three Given Integers

function findLargest(a, b, c) {
    return Math.max(a, b, c);
}

console.log(findLargest(10, 20, 15));  // 20

2. Explain Data Types with Example Program

let stringType = "Hello";
let numberType = 42;
let booleanType = true;
let objectType = { name: "John" };
let undefinedType;
let nullType = null;

console.log(typeof stringType, typeof numberType, typeof booleanType, typeof objectType, typeof undefinedType, typeof nullType);

3. Add Two Numbers Using a JavaScript Function

function addNumbers(a, b) {
    return a + b;
}

console.log(addNumbers(5, 10));  // 15

4. Convert a Given Number into Hours and Minutes

function convertToHoursAndMinutes(totalMinutes) {
    let hours = Math.floor(totalMinutes / 60);
    let minutes = totalMinutes % 60;
    return hours + " hours and " + minutes + " minutes";
}

console.log(convertToHoursAndMinutes(130));  // 2 hours and 10 minutes

5. Print Odd Numbers from 1 to 100

for (let i = 1; i <= 100; i++) {
    if (i % 2 !== 0) console.log(i);
}

6. Resize an Image on Mouse Events

const img = document.querySelector("img");

img.addEventListener("mouseover", () => img.style.width = "300px");
img.addEventListener("mouseout", () => img.style.width = "150px");

7. Perform a Binary Search

function binarySearch(arr, target) {
    let left = 0, right = arr.length - 1;
    while (left <= right) {
        let mid = Math.floor((left + right) / 2);
        if (arr[mid] === target) return mid;
        target < arr[mid] ? right = mid - 1 : left = mid + 1;
    }
    return -1;
}

console.log(binarySearch([1, 2, 3, 4, 5], 3));  // 2

8. Find the Most Frequent Item in an Array

function findMostFrequent(arr) {
    let freq = {};
    let maxFreq = 0, mostFrequent;
    arr.forEach(item => {
        freq[item] = (freq[item] || 0) + 1;
        if (freq[item] > maxFreq) {
            maxFreq = freq[item];
            mostFrequent = item;
        }
    });
    return mostFrequent;
}

console.log(findMostFrequent([1, 2, 3, 2, 1, 2]));  // 2

9. Check Palindrome Number

function isPalindrome(num) {
    return num.toString() === num.toString().split('').reverse().join('');
}

console.log(isPalindrome(121));  // true
console.log(isPalindrome(123));  // false

10. Print the Numbers from 0 to 50

for (let i = 0; i <= 50; i++) {
    console.log(i);
}

11. Multiply Two Numbers Using Function

function multiply(a, b) {
    return a * b;
}

console.log(multiply(5, 4));  // 20

12. Find if 1st January Will Be a Sunday Between 2014 and 2050

function isFirstJanSunday(year) {
    return new Date(year, 0, 1).getDay() === 0;
}

for (let year = 2014; year <= 2050; year++) {
    if (isFirstJanSunday(year)) console.log(`${year} Jan 1st is Sunday`);
}

13. Reverse the Elements of a Given Array

let arr = [1, 2, 3, 4, 5];
arr.reverse();
console.log(arr);  // [5, 4, 3, 2, 1]

14. Check Prime Number

function isPrime(num) {
    if (num <= 1) return false;
    for (let i = 2; i < num; i++) {
        if (num % i === 0) return false;
    }
    return true;
}

console.log(isPrime(11));  // true

15. Display Fibonacci Series

function fibonacci(n) {
    let a = 0, b = 1;
    while (n--) {
        console.log(a);
        [a, b] = [b, a + b];
    }
}

fibonacci(5);  // 0, 1, 1, 2, 3

16. Implement String Operations

let str = "Hello, World!";
console.log(str.toUpperCase());  // "HELLO, WORLD!"
console.log(str.toLowerCase());  // "hello, world!"
console.log(str.length);  // 13

17. Extract Values at Specified Indexes from a Specified Array

function extractValues(arr, indexes) {
    return indexes.map(i => arr[i]);
}

console.log(extractValues([1, 2, 3, 4, 5], [0, 2, 4]));  // [1, 3, 5]

18. Design a Form to Accept User ID and Password

<form>
    <label for="userID">User ID:</label><br>
    <input type="text" id="userID" name="userID"><br><br>
    <label for="password">Password:</label><br>
    <input type="password" id="password" name="password"><br><br>
    <input type="submit" value="Submit">
</form>

19. Get the Filename Extension

function getFileExtension(filename) {
    return filename.split('.').pop();
}

console.log(getFileExtension("example.jpg"));  // jpg

20. Test Whether the First Character of a String is Uppercase

function isFirstCharacterUppercase(str) {
    return str.charAt(0) === str.charAt(0).toUpperCase();
}

console.log(isFirstCharacterUppercase("Hello"));  // true
console.log(isFirstCharacterUppercase("hello"));  // false

21. Determine Whether a Given Year is a Leap Year or Not

function isLeapYear(year) {
    return (year % 4 === 0 && (year % 100 !== 0 || year % 400 === 0));
}

console.log(isLeapYear(2020));  // true

22. Create User Registration Form

<form>
    <label for="username">Username:</label><br>
    <input type="text" id="username" name="username"><br><br>
    <label for="email">Email:</label><br>
    <input type="email" id="email" name="email"><br><br>
    <input type="submit" value="Register">
</form>

23. Get the Current Date and Time

let currentDate = new Date();
console.log(currentDate.toLocaleString());  // Current date and time

24. Accept One Number and Multiply by 3

let number = prompt("Enter a number:");
alert(number * 3);

25. Multiply Two Numbers

function multiply(a, b) {
    return a * b;
}

console.log(multiply(6, 7));  // 42

26. Accept Two Numbers and Perform Subtraction

let num1 = prompt("Enter first number:");
let num2 = prompt("Enter second number:");
alert(num1 - num2);

27. Create Popup Box Alert and Confirm Box

alert("This is an alert box!");
let confirmResult = confirm("Do you want to proceed?");
console.log(confirmResult);

28. Find the Greater of Two Numbers

function findGreater(a, b) {
    return a > b ? a : b;
}

console.log(findGreater(10, 5));  // 10

29. Pass a Function as a Parameter

function greetUser(name, greetingFn) {
    greetingFn(name);
}

function sayHello(name) {
    console.log("Hello, " + name);
}

greetUser("Alice", sayHello);  // Hello, Alice

30. Display Current Day, Date, Month, Year, and Time

let currentDate = new Date();
console.log(currentDate.toDateString());  // Current date
console.log(currentDate.toTimeString());  // Current time


31. Implement Comparisons and Control Flow
let a = 10, b = 20;
if (a > b) {
    console.log(`${a} is greater than ${b}`);
} else {
    console.log(`${b} is greater than ${a}`);
}

32. Accept a Number from User and Calculate the Sum of Its Digits

function sumOfDigits(num) {
    let sum = 0;
    while (num > 0) {
        sum += num % 10;
        num = Math.floor(num / 10);
    }
    return sum;
}

console.log(sumOfDigits(1234));  // 10

33. Print Your Name

console.log("John Doe");

34. Generate a Random Hexadecimal Color Code

function generateHexColor() {
    return '#' + Math.floor(Math.random() * 16777215).toString(16);
}

console.log(generateHexColor());  // Random Hex Color

35. Swap Two Numbers Without Using a Third Variable

let a = 5, b = 10;
[a, b] = [b, a];
console.log(`a: ${a}, b: ${b}`);  // a: 10, b: 5

36. Rotate a String

function rotateString(str, n) {
    return str.slice(n) + str.slice(0, n);
}

console.log(rotateString("hello", 2));  // llohe

37. Get the First n Fibonacci Numbers

function fibonacci(n) {
    let a = 0, b = 1;
    let fib = [];
    while (n--) {
        fib.push(a);
        [a, b] = [b, a + b];
    }
    return fib;
}

console.log(fibonacci(5));  // [0, 1, 1, 2, 3]

38. Display the Current Day and Time in the Following Format

let now = new Date();
let day = now.toLocaleDateString();
let time = now.toLocaleTimeString();
console.log(`Today is ${day} and the time is ${time}`);

39. Change the Capitalization of All Letters in a Given String

function changeCase(str) {
    return str.split('').map(char => {
        return char === char.toUpperCase() ? char.toLowerCase() : char.toUpperCase();
    }).join('');
}

console.log(changeCase("Hello World"));  // hELLO wORLD

40. Generate All Permutations of an Array's Elements

function permute(arr) {
    let result = [];
    if (arr.length === 0) return [];
    if (arr.length === 1) return [arr];
    
    for (let i = 0; i < arr.length; i++) {
        let rest = arr.slice(0, i).concat(arr.slice(i + 1));
        let perms = permute(rest);
        for (let j = 0; j < perms.length; j++) {
            result.push([arr[i]].concat(perms[j]));
        }
    }
    return result;
}

console.log(permute([1, 2, 3]));

41. Sort the Elements of an Array in Ascending Order

let arr = [5, 2, 8, 1, 3];
arr.sort((a, b) => a - b);
console.log(arr);  // [1, 2, 3, 5, 8]

42. Demonstrate the Switch Statement

let day = 3;
switch (day) {
    case 1: console.log("Monday"); break;
    case 2: console.log("Tuesday"); break;
    case 3: console.log("Wednesday"); break;
    default: console.log("Invalid day");
}

43. Perform Arithmetic Operations of Two Numbers

let a = 10, b = 5;
console.log("Addition:", a + b);
console.log("Subtraction:", a - b);
console.log("Multiplication:", a * b);
console.log("Division:", a / b);

44. Display the Largest Integer Among Two Integers

let a = 8, b = 12;
console.log(Math.max(a, b));  // 12

45. Find the Factorial of a Number

function factorial(n) {
    if (n === 0) return 1;
    return n * factorial(n - 1);
}

console.log(factorial(5));  // 120

46. Check Whether the Given Number is Palindrome or Not

function isPalindrome(num) {
    let str = num.toString();
    return str === str.split('').reverse().join('');
}

console.log(isPalindrome(121));  // true
console.log(isPalindrome(123));  // false

47. Print the Elements of an Array

let arr = [1, 2, 3, 4, 5];
arr.forEach(item => console.log(item));

48. Define a User Defined Function for Sorting the Values in an Array

function customSort(arr) {
    return arr.sort((a, b) => a - b);
}

console.log(customSort([5, 3, 8, 1]));  // [1, 3, 5, 8]

49. Sort the Items of an Array

let arr = [10, 2, 5, 7, 4];
arr.sort((a, b) => a - b);
console.log(arr);  // [2, 4, 5, 7, 10]

50. Check Whether the Given String is Palindrome or Not

function isStringPalindrome(str) {
    return str === str.split('').reverse().join('');
}

console.log(isStringPalindrome("racecar"));  // true
console.log(isStringPalindrome("hello"));  // false

51. Accept Number and Display the Square of It

let num = prompt("Enter a number:");
alert(`The square of the number is: ${Math.pow(num, 2)}`);

52. Verify a Given Number is Even or Odd

let num = 15;
if (num % 2 === 0) {
    console.log("Even");
} else {
    console.log("Odd");
}

53. Validate Email ID Using Regular Expression

let email = "test@example.com";
let regex = /^[a-zA-Z0-9._-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,6}$/;
console.log(regex.test(email));  // true

54. Replace the Word 'System' with 'Web' in the Given Text

let text = "This is a system application.";
let newText = text.replace("system", "web");
console.log(newText);  // "This is a web application."

55. Print Corresponding Day of the Week Using Switch Statement

let dayNumber = 3;
switch (dayNumber) {
    case 1: console.log("Sunday"); break;
    case 2: console.log("Monday"); break;
    case 3: console.log("Tuesday"); break;
    case 4: console.log("Wednesday"); break;
    case 5: console.log("Thursday"); break;
    case 6: console.log("Friday"); break;
    case 7: console.log("Saturday"); break;
    default: console.log("Invalid day");
}

56. Convert Temperatures Between Celsius and Fahrenheit

function celsiusToFahrenheit(celsius) {
    return (celsius * 9/5) + 32;
}

function fahrenheitToCelsius(fahrenheit) {
    return (fahrenheit - 32) * 5/9;
}

console.log(celsiusToFahrenheit(25));  // 77
console.log(fahrenheitToCelsius(77));  // 25

57. Demonstrate Event Handling

let button = document.querySelector("button");
button.addEventListener("click", () => alert("Button clicked"));

58. Check Whether a Person is Eligible to Vote

let age = 20;
if (age >= 18) {
    console.log("Eligible to vote");
} else {
    console.log("Not eligible to vote");
}

59. Implement XMLHttpRequest (XHR) Object

let xhr = new XMLHttpRequest();
xhr.open("GET", "https://api.example.com", true);
xhr.onload = () => console.log(xhr.responseText);
xhr.send();

60. Determine Whether a Given Year is a Leap Year

function isLeapYear(year) {
    return (year % 4 === 0 && (year % 100 !== 0 || year % 400 === 0));
}

console.log(isLeapYear(2020));  // true

61. Display All Prime Numbers Between 1 and 100

function isPrime(num) {
    for (let i = 2; i < num; i++) {
        if (num % i === 0) return false;
    }
    return num > 1;
}

for (let i = 1; i <= 100; i++) {
    if (isPrime(i)) console.log(i);
}

62. Calculate Days Left Until Next Christmas

function daysUntilChristmas() {
    let today = new Date();
    let christmas = new Date(today.getFullYear(), 11, 25);  // December 25th
    if (today > christmas) {
        christmas.setFullYear(today.getFullYear() + 1);
    }
    let diff = christmas - today;
    return Math.floor(diff / (1000 * 60 * 60 * 24));
}

console.log(daysUntilChristmas());

63. Get the Window Width and Height Any Time the Window is Resized

window.addEventListener('resize', () => {
    console.log(`Window width: ${window.innerWidth}, height: ${window.innerHeight}`);
});

64. Find Whether a Number is Divisible by 2 and 3

let num = 12;
if (num % 2 === 0 && num % 3 === 0) {
    console.log(`${num} is divisible by 2 and 3.`);
} else {
    console.log(`${num} is not divisible by 2 and 3.`);
}

65. Prime Number Check

function isPrime(num) {
    if (num < 2) return false;
    for (let i = 2; i <= Math.sqrt(num); i++) {
        if (num % i === 0) return false;
    }
    return true;
}

console.log(isPrime(7));  // true
console.log(isPrime(10));  // false

66. Swap Two Variables

let a = 5, b = 10;
[a, b] = [b, a];
console.log(`a: ${a}, b: ${b}`);  // a: 10, b: 5

67. Accept Two Integers and Display the Result by Multiplying by 3

function multiplyBy3(num1, num2) {
    return (num1 * 3) + (num2 * 3);
}

console.log(multiplyBy3(5, 10));  // 45

68. Find Out the Factorial of a Given Number

function factorial(num) {
    if (num === 0) return 1;
    return num * factorial(num - 1);
}

console.log(factorial(6));  // 720

69. Convert a String to Title Case

function toTitleCase(str) {
    return str.replace(/\w\S*/g, (txt) => txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase());
}

console.log(toTitleCase("hello world!"));  // "Hello World!"

70. Accept a Number and Display the Sum of Its Digits

function sumOfDigits(num) {
    return num.toString().split('').reduce((sum, digit) => sum + +digit, 0);
}

console.log(sumOfDigits(12345));  // 15

71. Create a Simple Calculator

function calculator(num1, num2, operator) {
    switch (operator) {
        case '+': return num1 + num2;
        case '-': return num1 - num2;
        case '*': return num1 * num2;
        case '/': return num1 / num2;
        default: return "Invalid operator";
    }
}

console.log(calculator(5, 3, '+'));  // 8
console.log(calculator(5, 3, '/'));  // 1.6667

72. Reverse the Order of Characters in the String

function reverseString(str) {
    return str.split('').reverse().join('');
}

console.log(reverseString("hello"));  // "olleh"

73. Display the Current Day and Time

let now = new Date();
let currentDayTime = now.toLocaleString();
console.log(`Current date and time: ${currentDayTime}`);

74. Check If a Number is Odd or Even

let num = 15;
console.log(num % 2 === 0 ? 'Even' : 'Odd');

75. Get the Length of a JavaScript Object

let obj = { name: "John", age: 30, city: "New York" };
console.log(Object.keys(obj).length);  // 3

76. Sort a List of Elements Using Quick Sort

function quickSort(arr) {
    if (arr.length <= 1) return arr;
    let pivot = arr[arr.length - 1];
    let left = [], right = [];
    
    for (let i = 0; i < arr.length - 1; i++) {
        if (arr[i] < pivot) left.push(arr[i]);
        else right.push(arr[i]);
    }
    
    return [...quickSort(left), pivot, ...quickSort(right)];
}

console.log(quickSort([5, 3, 8, 1, 4]));  // [1, 3, 4, 5, 8]

77. Accept a String and Display It in Lowercase and Uppercase

let str = "Hello World";
console.log(str.toLowerCase());  // "hello world"
console.log(str.toUpperCase());  // "HELLO WORLD"

78. Factorial

function factorial(num) {
    if (num === 0) return 1;
    return num * factorial(num - 1);
}

console.log(factorial(4));  // 24

79. Using Any Five Events

document.getElementById("btnClick").addEventListener("click", () => alert("Button Clicked"));
document.getElementById("btnHover").addEventListener("mouseover", () => console.log("Mouse Over"));
document.getElementById("btnDoubleClick").addEventListener("dblclick", () => console.log("Double Clicked"));
document.getElementById("btnFocus").addEventListener("focus", () => console.log("Input Focused"));
document.getElementById("btnBlur").addEventListener("blur", () => console.log("Input Lost Focus"));

80. Read XML File and Display Data in a Neat Format

let xhr = new XMLHttpRequest();
xhr.open("GET", "data.xml", true);
xhr.onreadystatechange = function() {
    if (xhr.readyState === 4 && xhr.status === 200) {
        let xml = xhr.responseXML;
        let data = xml.getElementsByTagName("item");
        for (let i = 0; i < data.length; i++) {
            console.log(data[i].textContent);
        }
    }
};
xhr.send();

81. Fibonacci Series

function fibonacci(n) {
    let fib = [0, 1];
    for (let i = 2; i < n; i++) {
        fib.push(fib[i - 1] + fib[i - 2]);
    }
    return fib;
}

console.log(fibonacci(7));  // [0, 1, 1, 2, 3, 5, 8]

82. Remove the Whitespaces from a Given String

let str = "  Hello World!  ";
let newStr = str.trim();
console.log(newStr);  // "Hello World!"

83. Find the Most Frequent Item in an Array

function mostFrequent(arr) {
    let freqMap = {};
    let maxCount = 0;
    let mostFrequentItem = null;

    arr.forEach(item => {
        freqMap[item] = (freqMap[item] || 0) + 1;
        if (freqMap[item] > maxCount) {
            maxCount = freqMap[item];
            mostFrequentItem = item;
        }
    });

    return mostFrequentItem;
}

console.log(mostFrequent([1, 2, 3, 1, 2, 1]));  // 1

84. Show the Current Date and Time

let now = new Date();
console.log(now.toString());

85. Sum the Multiples of 3 and 5 Under 1000

let sum = 0;
for (let i = 0; i < 1000; i++) {
    if (i % 3 === 0 || i % 5 === 0) {
        sum += i;
    }
}
console.log(sum);  // 233168

86. Shuffle an Array

function shuffleArray(arr) {
    for (let i = arr.length - 1; i > 0; i--) {
        let j = Math.floor(Math.random() * (i + 1));
        [arr[i], arr[j]] = [arr[j], arr[i]];  // Swap elements
}
return arr;

}

console.log(shuffleArray([1, 2, 3, 4, 5])); // Randomly shuffled array


### 87. **Count the Vowels in a String**
```javascript
function countVowels(str) {
    let vowels = 'aeiou';
    return str.split('').filter(char => vowels.includes(char.toLowerCase())).length;
}

console.log(countVowels("Hello World"));  // 3

88. Find the Largest Number in an Array

let arr = [10, 5, 8, 22, 14];
console.log(Math.max(...arr));  // 22

89. Find the Index of an Element in an Array

let arr = [10, 20, 30, 40, 50];
console.log(arr.indexOf(30));  // 2

90. Remove All Duplicate Elements from an Array

let arr = [1, 2, 2, 3, 4, 4, 5];
let uniqueArr = [...new Set(arr)];
console.log(uniqueArr);  // [1, 2, 3, 4, 5]


91. Accept Two Numbers and Perform Addition

function addTwoNumbers(num1, num2) {
    return num1 + num2;
}

console.log(addTwoNumbers(10, 20));  // 30

92. Validate User Login Page

function validateLogin(username, password) {
    if (username === "user" && password === "password123") {
        return "Login successful!";
    } else {
        return "Invalid username or password.";
    }
}

console.log(validateLogin("user", "password123"));  // Login successful!
console.log(validateLogin("user", "wrongpass"));  // Invalid username or password.

93. Display Hello World on the Screen

document.body.innerHTML = "Hello, World!";

94. Develop a Calculator Application to Perform All the Arithmetic Operations

function calculator(num1, num2, operator) {
    switch (operator) {
        case '+': return num1 + num2;
        case '-': return num1 - num2;
        case '*': return num1 * num2;
        case '/': return num1 / num2;
        case '%': return num1 % num2;
        default: return "Invalid operator";
    }
}

console.log(calculator(5, 3, '+'));  // 8
console.log(calculator(5, 3, '*'));  // 15

95. Create a Simple Calculator in HTML

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Simple Calculator</title>
</head>
<body>
    <input id="num1" type="number" placeholder="Enter first number">
    <input id="num2" type="number" placeholder="Enter second number">
    <select id="operation">
        <option value="+">+</option>
        <option value="-">-</option>
        <option value="*">*</option>
        <option value="/">/</option>
    </select>
    <button onclick="performCalculation()">Calculate</button>
    <div id="result"></div>

    <script>
        function performCalculation() {
            let num1 = parseFloat(document.getElementById('num1').value);
            let num2 = parseFloat(document.getElementById('num2').value);
            let operator = document.getElementById('operation').value;

            let result;
            switch (operator) {
                case '+': result = num1 + num2; break;
                case '-': result = num1 - num2; break;
                case '*': result = num1 * num2; break;
                case '/': result = num1 / num2; break;
            }

            document.getElementById('result').innerText = `Result: ${result}`;
        }
    </script>
</body>
</html>

96. Read User Registration Details

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>User Registration</title>
</head>
<body>
    <form id="registrationForm">
        <label for="username">Username:</label>
        <input type="text" id="username" required><br>
        
        <label for="email">Email:</label>
        <input type="email" id="email" required><br>
        
        <label for="password">Password:</label>
        <input type="password" id="password" required><br>
        
        <button type="submit">Submit</button>
    </form>

    <div id="registrationResult"></div>

    <script>
        document.getElementById('registrationForm').addEventListener('submit', function(event) {
            event.preventDefault();

            let username = document.getElementById('username').value;
            let email = document.getElementById('email').value;
            let password = document.getElementById('password').value;

            document.getElementById('registrationResult').innerHTML = 
                `Registration Successful! Username: ${username}, Email: ${email}`;
        });
    </script>
</body>
</html>

97. Perform Arithmetic Operations

function arithmeticOperations(num1, num2) {
    return {
        sum: num1 + num2,
        difference: num1 - num2,
        product: num1 * num2,
        quotient: num1 / num2
    };
}

console.log(arithmeticOperations(10, 5));  
// {sum: 15, difference: 5, product: 50, quotient: 2}

98. Use Select Element of Form Tag

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Select Example</title>
</head>
<body>
    <form>
        <label for="colors">Choose a color:</label>
        <select id="colors">
            <option value="red">Red</option>
            <option value="blue">Blue</option>
            <option value="green">Green</option>
        </select>
        <button type="button" onclick="displaySelectedColor()">Submit</button>
    </form>

    <p id="selectedColor"></p>

    <script>
        function displaySelectedColor() {
            let selectedColor = document.getElementById('colors').value;
            document.getElementById('selectedColor').innerText = `You selected: ${selectedColor}`;
        }
    </script>
</body>
</html>

99. Print Multiplication Table of a Given Number Using Loop

function multiplicationTable(num) {
    for (let i = 1; i <= 10; i++) {
        console.log(`${num} x ${i} = ${num * i}`);
    }
}

multiplicationTable(5);

100. Reverse an Array

function reverseArray(arr) {
    return arr.reverse();
}

console.log(reverseArray([1, 2, 3, 4, 5]));  // [5, 4, 3, 2, 1]

101. Create an Object from the Given Key-Value Pairs

function createObject(keys, values) {
    let obj = {};
    for (let i = 0; i < keys.length; i++) {
        obj[keys[i]] = values[i];
    }
    return obj;
}

let keys = ["name", "age", "city"];
let values = ["John", 30, "New York"];
console.log(createObject(keys, values));  
// {name: "John", age: 30, city: "New York"}

102. Illustrate Callback Function

function greetUser(name, callback) {
    console.log(`Hello, ${name}!`);
    callback();
}

function sayGoodbye() {
    console.log("Goodbye!");
}

greetUser("John", sayGoodbye);

103. Add Items to a Blank Array and Display Them

let arr = [];
arr.push(10);
arr.push(20);
arr.push(30);
console.log(arr);  // [10, 20, 30]

104. Get the Current Date in HTML

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Current Date</title>
</head>
<body>
    <p id="currentDate"></p>

    <script>
        document.getElementById("currentDate").innerText = new Date().toLocaleDateString();
    </script>
</body>
</html>

105. Remove Items from a Dropdown List

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Remove Items from Dropdown</title>
</head>
<body>
    <select id="dropdown">
        <option value="apple">Apple</option>
        <option value="banana">Banana</option>
        <option value="cherry">Cherry</option>
    </select>
    <button onclick="removeOption()">Remove Option</button>

    <script>
        function removeOption() {
            let dropdown = document.getElementById('dropdown');
            dropdown.removeChild(dropdown.options[dropdown.selectedIndex]);
        }
    </script>
</body>
</html>

106. Link Banner Advertisement to Different URL

<a href="https://example.com">
    <img src="banner.jpg" alt="Banner Ad" />
</a>

107. Target a Given Value in a Nested JSON Object Based on the Given Key

let obj = {
    user: {
        name: "John",
        address: {
            city: "New York",
            zip: "10001"
        }
    }
};

function findValueByKey(obj, key) {
    for (let k in obj) {
        if (k === key) {
            return obj[k];
        }
        if (typeof obj[k] === "object") {
            return findValueByKey(obj[k], key);
        }
    }
}

console.log(findValueByKey(obj, "city"));  // "New York"

108. Check If a Number is Positive, Negative, or Zero

function checkNumber(num) {
    if (num > 0) {
        return "Positive";
    } else if (num < 0) {
        return "Negative";
    } else {
        return "Zero";
    }
}

console.log(checkNumber(5));  // Positive
console.log(checkNumber(-3));  // Negative
console.log(checkNumber(0));  // Zero

109. Find Area of Circle

function areaOfCircle(radius) {
    return Math.PI * Math.pow(radius, 2);
}

console.log(areaOfCircle(5));  // 78.53981633974483

110. Print Numbers from 1 to 10 Using For Loop

for (let i = 1; i <= 10; i++) {
    console.log(i);
}

111. Validate the Fields of Login Page

function validateLoginForm(username, password) {
    if (username === "" || password === "") {
        return "Please fill in both fields.";
    }
    if (username.length < 3) {
        return "Username must be at least 3 characters long.";
    }
    if (password.length < 6) {
        return "Password must be at least 6 characters long.";
    }
    return "Login successful!";
}

console.log(validateLoginForm("john", "pass123"));  // Login successful!
console.log(validateLoginForm("", "pass123"));  // Please fill in both fields.


112. Check Armstrong Number

function isArmstrongNumber(num) {
    let strNum = num.toString();
    let sum = 0;
    let length = strNum.length;

    for (let i = 0; i < length; i++) {
        sum += Math.pow(Number(strNum[i]), length);
    }

    return sum === num;
}

console.log(isArmstrongNumber(153));  // true
console.log(isArmstrongNumber(123));  // false

113. Form Validation

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Form Validation</title>
</head>
<body>
    <form id="myForm">
        <label for="username">Username:</label>
        <input type="text" id="username" required><br>

        <label for="email">Email:</label>
        <input type="email" id="email" required><br>

        <button type="submit">Submit</button>
    </form>

    <script>
        document.getElementById('myForm').addEventListener('submit', function(event) {
            event.preventDefault();
            let username = document.getElementById('username').value;
            let email = document.getElementById('email').value;

            if (username === "" || email === "") {
                alert("Please fill in all fields.");
            } else {
                alert("Form submitted successfully!");
            }
        });
    </script>
</body>
</html>

114. Remove Specified Elements from the Left of a Given Array of Elements

function removeLeftElements(arr, n) {
    return arr.slice(n);
}

console.log(removeLeftElements([1, 2, 3, 4, 5], 2));  // [3, 4, 5]

115. Declare and Initialize a Variable

let myVar = 10;
console.log(myVar);  // 10

116. Recursion Example

function factorial(n) {
    if (n === 0) {
        return 1;
    }
    return n * factorial(n - 1);
}

console.log(factorial(5));  // 120

117. Remove Duplicates from an Array

function removeDuplicates(arr) {
    return [...new Set(arr)];
}

console.log(removeDuplicates([1, 2, 3, 2, 4, 5, 3]));  // [1, 2, 3, 4, 5]

118. Calculate Area of Triangle

function areaOfTriangle(base, height) {
    return 0.5 * base * height;
}

console.log(areaOfTriangle(5, 10));  // 25

119. Merge Two Arrays While Removing All Duplicates

function mergeArrays(arr1, arr2) {
    return [...new Set([...arr1, ...arr2])];
}

console.log(mergeArrays([1, 2, 3], [3, 4, 5]));  // [1, 2, 3, 4, 5]

120. Count the Number of Unique Alphabets Present in a Given String

function countUniqueAlphabets(str) {
    let uniqueAlphabets = new Set(str.replace(/[^a-zA-Z]/g, '').toLowerCase());
    return uniqueAlphabets.size;
}

console.log(countUniqueAlphabets("Hello World!"));  // 7

121. Solve Quadratic Equation

function solveQuadratic(a, b, c) {
    let discriminant = Math.pow(b, 2) - (4 * a * c);
    
    if (discriminant > 0) {
        let root1 = (-b + Math.sqrt(discriminant)) / (2 * a);
        let root2 = (-b - Math.sqrt(discriminant)) / (2 * a);
        return `Roots are ${root1} and ${root2}`;
    } else if (discriminant === 0) {
        let root = -b / (2 * a);
        return `Root is ${root}`;
    } else {
        return "No real roots";
    }
}

console.log(solveQuadratic(1, -3, 2));  // Roots are 2 and 1

122. Demonstrate Arrays

let arr = [1, 2, 3, 4, 5];
arr.forEach(element => console.log(element));

123. Demonstrate Math Objects

let num = 16;
console.log(Math.sqrt(num));  // 4
console.log(Math.pow(2, 3));  // 8
console.log(Math.random());  // Random number

124. Accept a Number from the User and Find Its Factorial

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Factorial Calculator</title>
</head>
<body>
    <label for="num">Enter a number:</label>
    <input type="number" id="num">
    <button onclick="calculateFactorial()">Calculate Factorial</button>
    <p id="result"></p>

    <script>
        function calculateFactorial() {
            let num = document.getElementById('num').value;
            let result = 1;
            for (let i = 1; i <= num; i++) {
                result *= i;
            }
            document.getElementById('result').innerText = `Factorial: ${result}`;
        }
    </script>
</body>
</html>

125. Password Validation Based on the Following Conditions

function validatePassword(password) {
    if (password.length < 8) {
        return "Password must be at least 8 characters long.";
    }
    if (!/[A-Z]/.test(password)) {
        return "Password must contain at least one uppercase letter.";
    }
    if (!/[0-9]/.test(password)) {
        return "Password must contain at least one number.";
    }
    return "Password is valid.";
}

console.log(validatePassword("Pass1234"));  // Password is valid.
console.log(validatePassword("pass1234"));  // Password must contain at least one uppercase letter.

126. Get the Last Element from a Given Array

function getLastElement(arr) {
    return arr[arr.length - 1];
}

console.log(getLastElement([1, 2, 3, 4]));  // 4

127. Add Two Numbers

function add(num1, num2) {
    return num1 + num2;
}

console.log(add(10, 20));  // 30

128. Round Off the Integer Using Math Function

let number = 5.67;
console.log(Math.round(number));  // 6

129. Find the Largest Element in a Nested Array

let arr = [1, [2, 3], [4, 5], 6];
let largest = Math.max(...arr.flat());
console.log(largest);  // 6

130. Remove Items from a Drop-Down List

<select id="dropdown">
    <option value="apple">Apple</option>
    <option value="banana">Banana</option>
    <option value="cherry">Cherry</option>
</select>
<button onclick="removeOption()">Remove Banana</button>

<script>
    function removeOption() {
        let dropdown = document.getElementById('dropdown');
        for (let i = 0; i < dropdown.options.length; i++) {
            if (dropdown.options[i].value === 'banana') {
                dropdown.remove(i);
                break;
            }
        }
    }
</script>

131. Check Whether 1st January Will Be a Sunday Between 2014 and 2050

function checkSunday() {
    for (let year = 2014; year <= 2050; year++) {
        let date = new Date(year, 0, 1);
        if (date.getDay() === 0) {  // 0 is Sunday
            console.log(`${year} - January 1st is a Sunday`);
        }
    }
}

checkSunday();

132. Check Whether a Given Number is Perfect or Not

function isPerfectNumber(num) {
    let sum = 0;
    for (let i = 1; i < num; i++) {
        if (num % i === 0) {
            sum += i;
        }
    }
    return sum === num;
}

console.log(isPerfectNumber(6));  // true (6 is a perfect number)

133. Check Whether Entered Number is Prime or Not

function isPrime(num) {
    if (num < 2) return false;
    for (let i = 2; i <= Math.sqrt(num); i++) {
        if (num % i === 0) {
            return false;
        }
    }
    return true;
}

console.log(isPrime(5));  // true
console.log(isPrime(10));  // false

134. Get the Window Width and Height Any Time the Window is Resized

window.addEventListener('resize', function() {
    console.log(`Width: ${window.innerWidth}, Height: ${window.innerHeight}`);
});

135. Get Integers in the Range (x, y) Using Recursion

function getRange(x, y) {
    if (x <= y) {
        console.log(x);
        getRange(x + 1, y);
    }
}

getRange(1, 5);  // 1 2 3 4 5

136. Design a Simple Calculator

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Simple Calculator</title>
</head>
<body>
    <input type="number" id="num1" placeholder="Enter number 1">
    <input type="number" id="num2" placeholder="Enter number 2">
    <button onclick="add()">Add</button>
    <button onclick="subtract()">Subtract</button>
    <button onclick="multiply()">Multiply</button>
    <button onclick="divide()">Divide</button>
    <p id="result"></p>

    <script>
        function add() {
            let num1 = parseFloat(document.getElementById('num1').value);
            let num2 = parseFloat(document.getElementById('num2').value);
            document.getElementById('result').innerText = `Result: ${num1 + num2}`;
        }

        function subtract() {
            let num1 = parseFloat(document.getElementById('num1').value);
            let num2 = parseFloat(document.getElementById('num2').value);
            document.getElementById('result').innerText = `Result: ${num1 - num2}`;
        }

        function multiply() {
            let num1 = parseFloat(document.getElementById('num1').value);
            let num2 = parseFloat(document.getElementById('num2').value);
            document.getElementById('result').innerText = `Result: ${num1 * num2}`;
        }

        function divide() {
            let num1 = parseFloat(document.getElementById('num1').value);
            let num2 = parseFloat(document.getElementById('num2').value);
            document.getElementById('result').innerText = `Result: ${num1 / num2}`;
        }
    </script>
</body>
</html>

137. Demo Alert Box, Conditional Box, and Prompt Box

<button onclick="showAlert()">Show Alert</button>
<button onclick="showConfirm()">Show Confirm</button>
<button onclick="showPrompt()">Show Prompt</button>

<script>
    function showAlert() {
        alert("This is an alert box!");
    }

    function showConfirm() {
        let result = confirm("Do you want to proceed?");
        alert(result ? "You clicked OK!" : "You clicked Cancel!");
    }

    function showPrompt() {
        let userInput = prompt("Please enter your name:");
        alert(`Hello, ${userInput}!`);
    }
</script>

138. Construct a Pattern Using a Nested For Loop

function printPattern(n) {
    let result = '';
    for (let i = 1; i <= n; i++) {
        for (let j = 1; j <= i; j++) {
            result += '*';
        }
        result += '\n';
    }
    console.log(result);
}

printPattern(5);


Post a Comment

0 Comments