JavaScript | RegExp \uxxxx Metacharacter

Last Updated : 23 Apr, 2019

The RegExp \uxxxx Metacharacter in JavaScript is used to find the unicode character specified by a hexadecimal number xxxx. If match is found it returns the word else it returns NULL. Syntax:

/\uxxxx/

new RegExp("\\uxxxx")

Syntax with modifiers:

/\uxxxx/g

new RegExp("\\uxxxx", "g")

Example 1: This example matches the word corresponding to hexadecimal number 0047 i.e G in the whole string.

html

<!DOCTYPE html>
<html>

<head>
    <title>
        JavaScript RegExp \uxxxx Metacharacter
    </title>
</head>

<body style="text-align:center">
    
    <h1 style="color:green">
        GeeksforGeeks
    </h1>
    
    <h2>RegExp \uxxxx 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 = /\u0047/gi;
            var match4 = str1.match(regex4);

            document.getElementById("app").innerHTML
                    = "Found " + match4.length
                    + " match: " + match4;
        }
    </script>
</body>

</html>

Output: Before Clicking the button: hexax

After Clicking the button: hexax

Example 2: This example matches the hexadecimal number (0067) which corresponds to "g" and replaces it with "G".

html

<!DOCTYPE html>
<html>

<head>
    <title>
        JavaScript RegExp \uxxxx Metacharacter
    </title>
</head>

<body style="text-align:center">
    
    <h1 style="color:green">
        GeeksforGeeks
    </h1>
    
    <h2>RegExp \uxxxx Metacharacter</h2>
    
    <p>String: geeky@128</p>
    
    <button onclick="geek()">
        Click it!
    </button>
    
    <p id="app"></p>
    
    <script>
        function geek() {
            var str1 = "geeky@128";
            var regex4 = new RegExp("\\u0067", "gi");         
            var replace = "G";
            var match4 = str1.replace(regex4, replace);
            document.getElementById("app").innerHTML = 
                    " New string: " + match4;
        }
    </script>
</body>

</html>