Trimming Strings With Javascript

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:

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<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:

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/.../
    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 (“”).

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