chapter31

Ben Nadel has a nice post on trimming strings with javascript using regular expressions.

Note that the reg exp white space character ‘\s’ is used to match:

• space
• tab
• horizontal tab
• vertical tab
• line break

Sample code below:

<script type="text/javascript"> // Trims the beginning and trailing white space from a string. function trim( strText ){ return( strText.replace(new RegExp("^([s]+)|([s]+)$", "gm"), "") ); } // Trims the beinning white space from a string. function leftTrim( strText ){ return( strText.replace(new RegExp("^[s]+", "gm"), "") ); } // Trims the trailing white space from a string. function rightTrim( strText ){ return( strText.replace(new RegExp("[s]+$", "gm"), "") ); } </script>

Javascript: trimString.js

Update 25th March 2007: myString.replace(/^\s*|\s*$/g, "");

A basic breakdown:

/…/

Regular expressions in javascript are delimited with forward slashes

^

Outside the usual square brackets, the caret means look only at the beginning of the target string

|

Alternatation, meaning finding the left hand OR right have values

\s*

Denotes 0 to many white space characters

$

Means look only at the end of the target string

g

Makes the search global; finding all matches, not just the first match

Of course all we’re doing is replacing left and right white space with an empty string (”").

Related Pages

• How do I make sure a string is safe to use with JavaScript?
• Regular Expressions in JavaScript
• How do I trim the contents of a form?

This entry was posted on Tuesday, September 19th, 2006 at 11:23 pm and is filed under Javascript. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.