The regular expression mechanism adds extremely powerful searching tools to your programming. Here are some of the most commonly used regular expressions as they are used in JavaScript.
| Operator | Description | Sample pattern | matches | Doesn’t match |
| . (period) | Any single character except class="code">newline | . | E | \n |
| ^ | Beginning of string | ^a | apple | Banana |
| $ | End of string | a$ | banana | Apple |
| [characters] | Any of a list of characters in braces | [abcABC] | A | D |
| [char range] | Any character in the range | [a-zA-Z] | F | 9 |
| \d | Any single numerical digit | \d\d\d-\d\d\d\d | 123-4567 | The-thing |
| \b | A word boundary | \bthe\b | the | Theater |
| + | One or more occurrences of the previous character | \d+ | 1234 | Text |
| * | Zero or more occurrences of the previous character | [a-zA-Z]d* | B17, g | 7 |
| {digit} | Repeat preceding character digit times | \d{3}-\d{4} | 123-4567 | 999-99-9999 |
| {min, max} | Repeat preceding character at least min but not more than max times | .{2,4} | Ca, com, info | watermelon |
| (pattern segment) | Store results in pattern memory returned with code | ^(.).*\1$ | gig, wallow | Bobby |
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Source:http://www.dummies.com/how-to/content/add-searching-tools-with-regular-expression-operat.navId-405061.html
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