JavaScript If Statement

The JavaScript `if` statement is used to execute a block of code based on a specified condition. If the condition is true, the code block will run. If the condition is false, it is skipped. There are various ways to use the if statement in JavaScript.

JavaScript If Statement

The `if` statement in JavaScript allows conditional execution of code based on a specified condition. The code within the `if` block executes only if the condition is true.

Syntax 


if (condition) {
    // code to be executed if condition is true
}

Flowchart of JavaScript If statement

Example


let number = 10;
if (number > 0) {
    console.log("The number is positive.");
}

Output

The number is positive.

JavaScript If-Else Statement

The `if-else` statement is used to execute one block of code if a condition is true, and another block if the condition is false.

Syntax 


if (condition) {
    // code to be executed if condition is true
} else {
    // code to be executed if condition is false
}

Flowchart of JavaScript If...else statement

Example


let number = -5;
if (number > 0) {
    console.log("The number is positive.");
} else {
    console.log("The number is negative.");
}

Output

The number is negative.

JavaScript If-Else-If Statement

The `if-else-if` statement is a chain of multiple conditions that can be checked in sequence. It allows for testing multiple conditions in a single if-else structure.

Syntax


if (condition1) {
    // code to be executed if condition1 is true
} else if (condition2) {
    // code to be executed if condition2 is true
} else {
    // code to be executed if both conditions are false
}

Example


let grade = 85;
if (grade >= 90) {
    console.log("A grade");
} else if (grade >= 80) {
    console.log("B grade");
} else if (grade >= 70) {
    console.log("C grade");
} else {
    console.log("Fail");
}

Output

B grade

JavaScript Nested If Statement

The nested `if` statement contains one `if` statement inside another. The inner `if` statement is only executed if the condition in the outer `if` statement is true.

Syntax


if (condition1) {
    // code to be executed if condition1 is true
    if (condition2) {
        // code to be executed if condition2 is also true
    }
}

Example


let age = 20;
let hasID = true;

if (age >= 18) {
    if (hasID) {
        console.log("Allowed to enter");
    } else {
        console.log("ID required");
    }
} else {
    console.log("Not allowed to enter");
}

Output

Allowed to enter