Conditional statements in JavaScript are programming constructs that allow you to execute different blocks of code based on whether a specified condition evaluates to true or false. These statements enable you to create decision-making logic in your programs, controlling the flow of execution based on various circumstances.

The primary types of conditional statements in JavaScript are:

if Statement

The simplest form of a conditional statement. It checks a condition and executes a block of code if the condition is true.


if (condition) {
    // Code to execute if the condition is true
}

if-else Statement

This extends the if statement by providing an alternative block of code to execute if the condition is false.


if (condition) {
    // Code to execute if the condition is true
} else {
    // Code to execute if the condition is false
}

if-else if-else Statement

This allows you to check multiple conditions and execute corresponding blocks of code based on the first condition that evaluates to true.


if (condition1) {
    // Code to execute if condition1 is true
} else if (condition2) {
    // Code to execute if condition2 is true
} else {
    // Code to execute if none of the conditions are true
}

switch Statement

This is used to select one of many code blocks to be executed based on the value of an expression.


switch (expression) {
    case value1:
        // Code to execute if expression === value1
        break;
    case value2:
        // Code to execute if expression === value2
        break;
    // ... additional cases
    default:
        // Code to execute if no case matches
}