---
title: If-Else Statement
---
## Introduction

The `if` statement executes a statement if a specified condition is `true`. If the condition is `false`, another statement can be executed using the `else` statement.

**Note:** The `else` statement is optional.

```javascript
if (condition)
    /* do something */
else
    /* do something else */
```


Multiple `if...else` statements can be chained to create an `else if` clause. This specifies a new condition to test and can be repeated to test multiple conditions, checking until a true statement is presented to execute.

```javascript
if (condition1)
    /* do something */
else if (condition2)
    /* do something else */
else if (condition3)
    /* do something else */
else
    /* final statement */
```

**Note:** If you want to execute more than one statement in the `if`, `else` or `else if` part, curly braces are required around the statements:

```javascript
if (condition) {
    /* do */
    /* something */
    /* with multiple statements */
} else {
    /* do something */
    /* else */
}
```

<a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/if...else' target='_blank' rel='nofollow'>MDN link</a> | <a href='https://msdn.microsoft.com/en-us/library/85yyde5c.aspx' target='_blank' rel='nofollow'>MSDN link</a>

### Additional ternary operator
For a simple operation like assigning a value to a variable conditionally you can use a ternary operator, which is a shorthand syntax for an `if...else` clause in JavaScript
```javascript
// Normal if...else
let num  = 1;
if (someCondition){
    num = 1;
} else {
    num = 0;
}

// Using ternary operator
const num = someCondition ? 1 : 2;
// condition ? true case : false case
```

## Examples

**Using** `if...else`:
```javascript
    // If x=5 then z=7 and q=42 else z=19.
    if (x === 5) {
      z = 7;
      q = 42;
    }else{
      z = 19;
    }
```

**Using** `else if`:
```javascript
    // Categorising any number x as a small, medium, or large number  
    if (x < 10)
        return "Small number";
    else if (x < 50)
        return "Medium number";
    else if (x < 100)
        return "Large number";
    else {
        flag = 1;
        return "Invalid number";
    }
```

**Using** `if` **alone**:
```javascript
    // This function can also act as a Boolean
    if (x < 30) {
        return "true";
    }