In this tutorial, we will learn about if-else statements in JavaScript. We will cover the basics of conditional execution using if-else statements.
An if-else statement is a conditional statement that executes one block of code if a specified condition is true, and another block of code if the condition is false.
The syntax for the if-else statement in JavaScript is:
if (condition) {
// Code block to execute if condition is true
} else {
// Code block to execute if condition is false
}
The if-else statement evaluates the specified condition. If the condition is true, the code block inside the if statement is executed; otherwise, the code block inside the else statement is executed.
num
.num
.num
is even or odd.num
is even or odd.let num = 10;
if (num % 2 === 0) {
console.log(num + ' is even.');
} else {
console.log(num + ' is odd.');
}
10 is even.
str
.str
.str
starts with a specific value.let str = 'Hello, world!';
if (str.startsWith('Hello')) {
console.log('String starts with 'Hello'.');
} else {
console.log('String does not start with 'Hello'.');
}
String starts with 'Hello'.
num
.num
.num
is positive or negative.num
is positive or negative.let num = -5;
if (num > 0) {
console.log(num + ' is positive.');
} else {
console.log(num + ' is negative or zero.');
}
-5 is negative or zero.