Small plugin that justifies a menu using jquery

jquery.LImenuPadding.js

/*
  Tested with http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js
  in FF Mac, Safari Mac, Chrome Mac, Opera Mac, FF PC, IE 7 and 8, IE 6 works with css hack on LIs _width:3px;
  Requirements: Menu structure has to be <ul><li><a...
  <ul> must have a class or id
*/  

/* PAD LIs EVENLY */	  
(function($){  
    $.fn.limenupadding = function(options) {  
	return this.each(function(){
	    var $this = $(this);
	    
	    var opts = $.extend({
		exclude: 0 // exclude from calculation for end caps: positive interger
	    },options);
	    var exclude = opts.exclude;
	    
	    var lisTotalWidth = 0;	
	    var ulWidth = ($this.width() - exclude); /* exclude is adjustment amount. Used here to subtract end caps */
	    
	    // Remove the first and last item.
	    ulWidth = ulWidth - $this.children(':first-child').width();
	    ulWidth = ulWidth - $this.children(':last-child').width();
	    
	    var liCount = $this.children().size() - 1;
	    
	    $this.children().not(':last-child').not(':first-child').each(function() {
		lisTotalWidth += $(this).width();
	    });
	    
	    var difference = ulWidth - lisTotalWidth;
	    if (difference < 0 ) {
		alert ("Total width of menu items in '" + $this.attr('class') + "' exceeds available space. Use fewer menu items, use shorter labels, or make menu wider.");
	    }
	    var paddingLRraw = (difference/liCount)/2;
	    
	    var paddingLRfloor = Math.floor(paddingLRraw); /* round down to be safe, if too much pad li may wrap */
	    /* distribute computed padding across all LIs */
	    $this.children().not(':last-child').not(':first-child').children().css({'padding-left': paddingLRfloor, 'padding-right': paddingLRfloor});
	    $this.children(':last-child').children().css({'padding-left': paddingLRfloor});
	    $this.children(':first-child').children().css({'padding-right': paddingLRfloor});
	    
	    /* if lis don't space perfectly, how much filler do we need to even them out? */
	    var paddingRemainder = paddingLRfloor * (liCount * 2);
	    var filler = difference - paddingRemainder; 
	    /* distribute 1px of filler across several LIs, Mozilla has a bug that can cause a wrap in some cases. 1px breathing room seems to correct it. */
	    if ($.browser.mozilla) {
		filler = filler -1;
	    }
	    var filler1 = filler/2;
	    var filler2 = filler1;
	    filler1 = Math.floor(filler1);
	    filler2 = Math.ceil(filler2);
	    for ( var i=0; i < filler1; i++) {
		$this.children().not(':last-child').not(':first-child').children(':eq(' + i + ')').css({'padding-left': (paddingLRfloor + 1)});
	    }
	    for ( var i=0; i < filler2; i++) {
		$this.children().not(':last-child').not(':first-child').children(':eq(' + i + ')').css({'padding-right': (paddingLRfloor + 1)});
	    }
	    
	    $this.children(':first-child').children().css({'padding-left': 0});
	    $this.children(':last-child').children().css({'padding-right': 0});
	    
	    
	    /*
	      alert ("Menu id: " + $(this).attr('id') + "\nMenu class: " + $(this).attr('class') + "\nMenu width: " + (this).width() + "px\nPixels to exclude: " + exclude + "px\nSum of <li> widths: " + lisTotalWidth + "px\nDifference: " + difference  + "px\n<li> count: " + liCount  + "\nComputed pad amount raw: " + paddingLRraw  + "\nComputed pad amount rounded down: " + paddingLRfloor  + "\nSum of <li>s with computed padding: " + paddingRemainder  + "px\nFiller needed: " + filler  + " (" + difference + "px - " + paddingRemainder + "px)\n(1px applied as LEFT pad on " + filler1 + " <li>)\n(1px applied as RIGHT pad on " + filler2 + " <li>)");
	    */
	});
    };  
})(jQuery);