JavaScript RegExp \udddd Metacharacter
Example
Do a global search for the hexadecimal number 0057 (W) in a string:
let text = "Visit W3Schools. Hello World!";
let pattern = /\u0057/g;
Try it Yourself »
Definition and Usage
The \udddd metacharacters matches Unicode characters specified by a hexadecimal number (dddd).
Browser Support
/\udd/ is an ECMAScript1 (ES1) feature.
ES1 (JavaScript 1997) is fully supported in all browsers:
| Chrome | Edge | Firefox | Safari | Opera | IE |
| Yes | Yes | Yes | Yes | Yes | Yes |
Syntax
new RegExp("\\udddd")
or simply:
/\udddd/
Syntax with modifiers
new RegExp("\\udddd", "g")
or simply:
/\udddd/g
Regular Expression Search Methods
In JavaScript, a regular expression text search, can be done with different methods.
With a pattern as a regular expression, these are the most common methods:
| Example | Description |
|---|---|
| text.match(pattern) | The String method match() |
| text.search(pattern) | The String method search() |
| pattern.exec(text) | The RexExp method exec() |
| pattern.test(text) | The RegExp method test() |
