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’.
function func() {
let str = 'Geeks for Geeks';
let value = str.startsWith('Gee');
console.log(value);
}
func();
Output
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
function func() {
// Original string
let str = 'It is a great day.';
let value = str.startsWith('great', 8);
console.log(value);
}
// Function call
func();
Output
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.w3wiki.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.'));
Output
true false false true
We have a complete list of Javascript String Methods, to check those please go through the Javascript String Complete Reference article.
Supported Browser:
JavaScript String startsWith() Method
The 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.