Substring check in JavaScript
The includes() method can be used to check whether a string contains a specified substring. It returns true if substring is present. This method is case sensitive.
Syntax:
string.includes(searchvalue, start)
Parameters: This method requires 2 parameters :-
- searchvalue: Required. It specifies the substring that needs to be searched.
- start: Optional. It specifies the index from where the searching is performed. By default it is 0.
Return Value: True if the specified substring is present in string else returns false.
Example:
<!DOCTYPE html><html> <body> <h1>Welcome to GeeksforGeeks</h1> <p>Click the button to check whether <b>Geeks</b> is present in the below string. </p> Hello there! Welcome to GeeksforGeeks.<br><br> <button onclick="myFunction()">Try it</button> <p id="display"></p> <!--script to check string contains the specified substring.--> <script> function myFunction() { var str = "Hello there! Welcome to GeeksforGeeks."; var flag = str.includes("Geeks"); document.getElementById("display").innerHTML = flag; } </script> </body></html> |
Output:
Before clicking try it button:
After clicking try it button:
Supported Browsers: The browser supported by includes() Method are listed below:
- Google Chrome 41
- Apple Safari 9
- Firefox 40
- Opera 28
- Edge 12.0
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