JavaScript | RegExp \0 Metacharacter

Last Updated : 22 Apr, 2019

The RegExp \0 Metacharacter in JavaScript is used to find the NULL character. If it is found it returns the position else it returns -1.

Syntax:

/\0/

new RegExp("\\0")

Example 1: This example searches for the Null character in the string.

<!DOCTYPE html>
<html>
  
<head>
    <title>
        JavaScript RegExp \0 Metacharacter
    </title>
</head>
  
<body style="text-align:center">
      
    <h1 style="color:green">
        GeeksforGeeks
    </h1>
      
    <h2>RegExp \0 Metacharacter</h2>
      
    <p>Input String: GeeksforGeeks@_123_$</p>
      
    <button onclick="geek()">
        Click it!
    </button>
      
    <p id="app"></p>
      
    <script>
        function geek() {
            var str1 = "GeeksforGeeks@_123_$";
            var regex4 = /\0/;
            var match4 = str1.search(regex4);
            if(match4 == -1) {         
                document.getElementById("app").innerHTML
                    = "No Null charcters present. ";
            } 
            else {
                document.getElementById("app").innerHTML
                    = "Index of Null character: " + match4;
            }
        }
    </script>
</body>
  
</html>                    

Output:
Before Clicking the button:
bnul
After Clicking the button:
bnul

Example 2: This example searches the position of the NULL character in the string.

<!DOCTYPE html>
<html>
  
<head>
    <title>
        JavaScript RegExp \0 Metacharacter
    </title>
</head>
  
<body style="text-align:center">
      
    <h1 style="color:green">
        GeeksforGeeks
    </h1>
      
    <h2>RegExp \0 Metacharacter</h2>
      
    <p>String: 123ge\0eky456</p>
      
    <button onclick="geek()">
        Click it!
    </button>
      
    <p id="app"></p>
      
    <script>
        function geek() {
            var str1 = "123ge\0eky456";
            var regex4 = new RegExp("\\0");         
            var match4 = str1.search(regex4);
            document.getElementById("app").innerHTML = 
                " Index of NULL character: " + match4;
        }
    </script>
</body>
  
</html>                    