JavaScript | RegExp \xxx Metacharacter

Last Updated : 22 Apr, 2019

The RegExp \xxx Metacharacter in JavaScript is used to find the character specified by an octal number xxx. If the match is found it returns the character else it returns NULL. Syntax:

/\xxx/

new RegExp("\\xxx")

Syntax with modifiers:

/\xxx/g

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

Example 1: This example returns the character corresponding to octal number 107 i.e G in the whole string.

html

<!DOCTYPE html>
<html>

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

<body style="text-align:center">
    
    <h1 style="color:green">
        GeeksforGeeks
    </h1>
    
    <h2>RegExp \xxx 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 = /\107/gi;
            var match4 = str1.match(regex4);

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

</html>

Output: Before Clicking the button: backx

After Clicking the button: backx

Example 2: This example matches the octal number (147) which corresponds to "g" and replaces it with "G".

html

<!DOCTYPE html>
<html>

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

<body style="text-align:center">
    
    <h1 style="color:green">
        GeeksforGeeks
    </h1>
    
    <h2>RegExp \xxx 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("\\147", "gi");         
            var replace = "G";
            var match4 = str1.replace(regex4, replace);
            document.getElementById("app").innerHTML = 
            " New string: " + match4;
        }
    </script>
</body>

</html>