JavaScript String startsWith() Method

JavaScript String startsWith() method checks if a string starts with the characters of a specified string.

Syntax

str.startsWith( searchString , position )

Parameters

This method accepts two parameters as mentioned above and described below: 

• searchString: It is a required parameter. It stores the string that needs to be searched.
• start: It determines the position in the given string from where the searchString is to be searched. The default value is zero.

Return Value

This method returns the Boolean value true if the searchString is found else returns false.

String startsWith() Examples

Example 1: Checking if a String Starts with a Specific Substring

The function checks if the string ‘str’ starts with the substring ‘Gee’. It returns true because ‘Geeks for Geeks’ starts with ‘Gee’.

let str = 'Geeks for Geeks';
let value = str.startsWith('Gee');

console.log(value);

true

Example 2: Checking if a String Starts with a Specific Substring at a Given Position

The function checks if the string ‘str’ starts with the substring ‘great’ starting from index 8. It returns true because ‘great day.’ starts at index 8 in the string.

// JavaScript to illustrate
// startsWith() method

// Original string
let str = 'It is a great day.';
let value = str.startsWith('great', 8);

console.log(value);

true

Example 3: Checking if a URL or Filename Starts with a Specific Substring

The code checks if the URL starts with “https://” and if the filename starts with “.js”. It returns true for the URL starting with “https://” and false for the filename starting with “.js”.

// Checking if a URL starts with "https://"
let url ='https://www.geeksforgeeks.org/';

console.log(url.startsWith('https://')); 
console.log(url.startsWith('http://'));

//Checking if a filename starts with a specific extension
let filename = 'script.js';

console.log(filename.startsWith('.js')); 
console.log(filename.startsWith('script.'));

true
false
false
true

Supported Browser:

• Google Chrome 41
• Edge 12
• Firefox 17
• Opera 28
• Safari 9