Doug saves the day with a more streamlined plugin and feature suggestions

jquery.fastertrim.js

/*
* jQuery fasterTrim Plugin
* version: 1.0.5
* @requires jQuery v1.0.x or later
*
* dual licensed under the MIT and GPL licenses:
*	http://www.opensource.org/licenses/mit-license.php
*	http://www.opensource.org/licenses/gpl-2.0.php
*
* @version $Id: jquery.fastertrim.js 5 2010-03-12 12:00:00Z $
* @author	Travis Hardiman https://forum.jquery.com/user/travis.hardiman	http://travis.servebeer.com
*	with code/help from: Steven Levithan, Ralph Whitbeck, D. Jovanovic, John Resig, Doug Neiner, Dave Methvin
*
*	2010-02-22 - initial creation
*	2010-03-04 - perf improvements, formatting
*	2010-03-04 - Doug's help & suggestions: http://gist.github.com/gists/322211
*	2010-03-08 - Dave's suggestions on separate functions, added GPL, added .trimAttr()
*	2010-03-11 - suggestions from DBJ, John's code from core, added .trimLeft() and .trimRight()
*	2010-03-12 - more of John's code from core, .unicodeTrim()
*
*/

/**
* Trims strings faster than default jQuery.trim() (up until 1.4.3) demo: http://jsbin.com/izici3/56
* Usage: 
* 
* // these now use the fasterTrim functions
* $.trim( " string " );	// === "string"
* $.trimLeft( " string " );	// === "string "
* $.trimRight( " string " );	// === " string"
* 
* // this uses the Levithan trim function, better for larger strings
* // (see http://blog.stevenlevithan.com/archives/faster-trim-javascript )
* $.levithanTrim( " string " );
* 
* OR:
* 
* $( element ).trimHtml();	// returns jQuery object with HTML trimmed
* $( element ).trimText();	// returns jQuery object with text trimmed
* $( element ).trimAttr( attrToTrim );	// returns jQuery object with the attribute attrToTrim trimmed
* 
*/

(function( jQuery ) {
	// simple values to cache
	var empty = "",
		// test for NBSP bug in IE
		//TODO: test for other \s bugs as well? http://xregexp.com/tests/unicode.html
		hasNbspBug = ( !/\s/.test( "\xA0" ) ),
		// do you have native trim? http://jsbin.com/unaqa3/8
		hasNativeTrim = jQuery.isFunction( String.prototype.trim ),
		hasNativeTrimLeft = jQuery.isFunction( String.prototype.trimLeft ),
		hasNativeTrimRight = jQuery.isFunction( String.prototype.trimRight ),
		// default regex for trimming beginning of string
		rtrimLeft = /^\s+/,
		// default regex for trimming end of string
		rtrimRight = /\s+$/,
		// default regex for matching whitespace
		whitespace = /\s/,
		
		trimLeft = ( hasNativeTrimLeft ) ? function( text ) {
			return ( text == null ) ? 
				empty : 
				String.prototype.trimLeft.call( text );
		} : function( text ) {
			return ( text == null ) ? 
				empty : 
				text.toString().replace( rtrimLeft, empty );
		},
		
		trimRight = ( hasNativeTrimRight ) ? function( text ) {
			return ( text == null ) ? 
				empty : 
				String.prototype.trimRight.call( text );
		} : function( text ) {
			return ( text == null ) ? 
				empty : 
				text.toString().replace( rtrimRight, empty );
		},
		
		trim = ( hasNativeTrim ) ? function( text ) {
			return ( text == null ) ? 
				empty : 
				String.prototype.trim.call( text );
		} : function( text ) {
			return ( text == null ) ? 
				empty : 
				text.toString().replace( rtrimLeft, empty ).replace( rtrimRight, empty );
		},
		
		// pass through to native trim since that's still faster
		levithanTrim = ( hasNativeTrim ) ? trim : function ( text ) {
			if ( text == null ) {
				return empty;
			} else {
				var str = text.toString().replace( rtrimLeft, empty ),
					i = str.length;
				while ( whitespace.test( str.charAt( --i ) ) ) { }
				return str.slice( 0, i + 1 );
			}
		},
				
		// focus on trimming all visual white-space instead of performance (native trim cannot be relied upon, since it may have bugs)
		unicodeWhitespace = ["\u1680" , "\u180e" , "\u2000" , "\u2001" , "\u2002" ,"\u2003", "\u2004", "\u2005", "\u2006", "\u2007", "\u2008", "\u2009", "\u200a", "\u200b", "\u2028", "\u2029", "\u202F", "\u205f", "\u3000"],
		unmatchedUnicode = (function () {
			// return string of escaped unicode chars not matched by \s
			var unmatched = ( hasNbspBug ) ? "\\xA0" : empty;
			for ( var i = unicodeWhitespace.length; i--; ) {
				if ( !/\s/.test( unicodeWhitespace[i] ) ) {
					unmatched += "\\u" + unicodeWhitespace[i].charCodeAt(0).toString(16);
				}
			}
			return unmatched;
		})(),
		runicodeTrimLeft = new RegExp("^[\\s" + unmatchedUnicode + "]+"),
		runicodeTrimRight = new RegExp("[\\s" + unmatchedUnicode + "]+$"),
		unicodeTrim = function ( text ) {
			return ( text == null ) ? 
				empty : 
				text.toString().replace( runicodeTrimLeft, empty ).replace( runicodeTrimRight, empty );
		};

		
	if ( hasNbspBug ) {
		rtrimLeft = /^[\s\xA0]+/;
		rtrimRight = /[\s\xA0]+$/;
		whitespace = /[\s\xA0]/;
	}

	jQuery.fasterTrim = {
		hasNbspBug: hasNbspBug,
		hasNativeTrim: hasNativeTrim,
		rtrimLeft: rtrimLeft,
		rtrimRight: rtrimRight,
		whitespace: whitespace,
		trimLeft: trimLeft,
		trimRight: trimRight,
		trim: trim,
		levithanTrim: levithanTrim,
		unmatchedUnicode: unmatchedUnicode,
		runicodeTrimLeft: runicodeTrimLeft,
		runicodeTrimRight: runicodeTrimRight,
		unicodeTrim: unicodeTrim
	};

	jQuery.fn.trimHtml = function() {
		return this.each( function() {
			var $el = jQuery( this );
			$el.html( jQuery.fasterTrim.trim( $el.html() ) );
		});
	};

	jQuery.fn.trimText = function() {
		return this.each( function() {
			var $el = jQuery( this );
			$el.text( jQuery.fasterTrim.trim( $el.text() ) );
		});
	};

	jQuery.fn.trimAttr = function( attrToTrim ) {
		return this.each( function() {
			var $el = jQuery( this );
			$el.attr( attrToTrim, jQuery.fasterTrim.trim( $el.attr( attrToTrim ) ) );
		});
	};

	// overwrite jQuery's default trim after backing it up in _trim
	jQuery.fasterTrim._trim = jQuery.trim;
	jQuery.trim = jQuery.fasterTrim.trim;
	// add new functions
	jQuery.trimLeft = jQuery.fasterTrim.trimLeft;
	jQuery.trimRight = jQuery.fasterTrim.trimRight;
	jQuery.levithanTrim = jQuery.fasterTrim.levithanTrim;
	jQuery.unicodeTrim = jQuery.fasterTrim.unicodeTrim;

})( jQuery );