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

My Personal Notes

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ProgrammerAnvesh

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