JavaScript RegExp Complete Reference
The RegExp stands for Regular Expression. A regular expression is a sequence of characters that forms a search pattern. The search pattern can be used for text search and text to replace operations. A regular expression can be a single character or a more complicated pattern.
Syntax:
new RegExp("(Regular Expressioncharactersnonword)")Example: This example searches the words whose starting character is “A” and ending character is “C” with only one character in between them.
HTML
<body style="text-align:center"> <h1 style="color:green"> GeeksforGeeks </h1> <h2>RegExp . Metacharacter</h2> <p> Input String: ABC, A3C, A C, AXXCC! </p> <button onclick="geek()"> Click it! </button> <p id="app"></p> <script> function geek() { var str1 = "ABC, A3C, A C, AXXCC!"; var regex4 = /A.C/g; var match4 = str1.match(regex4); document.getElementById("app").innerHTML = "Found " + match4.length + " matches: " + match4; } </script></body> |
Output:
The complete list of JavaScript RegExp is listed below:
RegExp | Description |
|---|---|
| Metacharacter | Search single characters, except line terminator or newline. |
| m | Perform multiline matching. |
| \r | The RegExp \r Metacharacter carriage return characters. |
| (x|y) | Search any of the specified characters (separated by |). |
| \xxx | Find the character specified by an octal number xxx. |
| \W | Find the non word character i.e. characters which are not from a to z, A to Z, 0 to 9. |
| [^abc] | Search for any character which is not between the brackets. |
| g | Find all the occurrences of the pattern instead of stopping after the first match i.e it performs a global match. |
| [0-9] | Search any digit which is between the brackets. |
| \s | Find the whitespace characters. |
| \b | Find a match at the beginning or end of a word |
| i | Perform case-insensitive matching in the string. |
| \n | The RegExp \n Metacharacter in JavaScript is used to find the newline character. |
| [^0-9] | Search for any digit which is not between the brackets. |
| \B | Find a match that is not present at the beginning or end of a word. |
| \f | Find the form feed character (form feed is a page-breaking ASCII control character). |
| \w | Find the word character i.e. characters from a to z, A to Z, 0 to 9. It is the same as [a-zA-Z_0-9]. |
| \d | Search digit characters. It is the same as [0-9]. |
| \t | If it is found it returns the position else it returns -1. |
| \D | Search non-digit characters i.e all the characters except digits. It is the same as [^0-9]. |
| \0 | Find the NULL character. If it is found it returns the position else it returns -1. |
| \v | Find the vertical tab character. If it is found it returns the position else it returns -1. |
| * | Find the match of any string that contains zero or more occurrences of m. |
| {X,} | Find the match of any string that contains a sequence of m, at least X times, where X is a number. |
| ?! | Find the match of any string which is not followed by a specific string m. |
| {X} | Find the match of any string that contains a sequence of m, X times where X is a number. |
| ^ | Find the match of any string which contains m at the beginning of it. |
| ? | Find the match of any string that contains zero or one occurrence of m. |
| $ | Find the match of any string which contains m at the end of it. |
| + | Find the match of any string that contains at least one m. |
| \uxxxx | Find the Unicode character specified by a hexadecimal number XXXX. |
| {X,Y} | Find the match of any string that contains a sequence of m, X to Y times where X, Y must be numbered. |
| toString() | Return the string value of the regular expression. |
| test() | If there is a match this method returns true else it returns false. |
| ignoreCase | Specify whether the “i” modifier is set or not |
| constructor | Return the function that created the RegExp |
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