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Chandru P
Chandru P

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Conditional Statements In Javascript.

#javascript #beginners #tutorial #webdev

JavaScript conditional statements are used to make decisions in a program based on given conditions. They control the flow of execution by running different code blocks depending on whether a condition is true or false.

  • Conditions are evaluated using comparison and logical operators.

  • They help in building dynamic and interactive applications by responding to different inputs.

How to use the if statement in JavaScript
The if statement is the basic form of a conditional logic in JavaScript. It checks whether a condition is true and runs a block of code if it is.

Types of Conditional Statements

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1.if Statement;-

The if statement checks a condition written inside parentheses. If the condition evaluates to true, the code inside {} is executed; otherwise, it is skipped.

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  • Executes code only when a specified condition is true.

  • Useful for making simple decisions in a program.

Syntax:

let x = 20;

if (x % 2 === 0) {
    console.log("Even");
}

if (x % 2 !== 0) {
    console.log("Odd");
};
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output;- 

  `Even`
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2. if-elseStatement

The if-else statement executes one block of code if a condition is true and another block if it is false. It ensures that exactly one of the two code blocks runs.

(https://dev-to-uploads.s3.amazonaws.com/uploads/articles/fhz2poxn0kg65lpp99fy.png)

  • Used when there are two possible outcomes.

  • The else block runs when the if condition is not satisfied.

let age = 25;

if (age >= 18) {
    console.log("Adult")
} else {
    console.log("Not an Adult")
};
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Output
Adult

3. else if Statement

The else if statement is used to test multiple conditions in sequence. It executes the first block whose condition evaluates to true.

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  • Allows checking more than two conditions.

  • Evaluated from top to bottom until a true condition is found.

const x = 0;

if (x > 0) {
    console.log("Positive.");
} else if (x < 0) {
    console.log("Negative.");
} else {
    console.log("Zero.");
};
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Output;
Zero.
Summary

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There are different types of conditional statements in JavaScript, just as they are in other programming languages but I will focus on these two:

The most common conditional statement used often is the IF-ELSE statement. just as the name goes, if something is true, do something. otherwise, do something else.

study the image below for reference:

This is the syntax for the if-else statement:

if (condition) {
    // If the condition is true, this code block will run
} else {
    // If the condition is false, this code block will run
}
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In some cases, you might want to check several, related conditions. In those scenarios, you can use an else-if to evaluate the extra conditions.

if (condition) {
    // If the condition is true, this code block will run, and code execution
    // will stop.
} else if (conditiontwo) {
    // If the first condition is false, this code block will run if conditiontwo
    // is true
} else if (condition_n) {
    // If the previous conditions are both falsy, this code block will run if
    // condition_n is true
} else {
    // If all conditions are false, this code block will run
}
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     [`https://miro.medium.com/v2/resize:fit:640/format:webp/1*GDrqEYJgxTHzKbKHaMkUiA.png`](url)
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Conditional statements in JavaScript rely on a set of three basic syntax keywords: if, else and else if.

(https://dev-to-uploads.s3.amazonaws.com/uploads/articles/sf74tmvm8dgsmfki4rlj.png)<br>

This is the syntax for the if-else statement.

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