(function($) {

	/**
	 * helper variables and function
	 */
	$.ifixpng = function(customPixel) {
		$.ifixpng.pixel = customPixel;
	};
	
	$.ifixpng.getPixel = function() {
		return $.ifixpng.pixel || 'images/pixel.gif';
	};
	
	var hack = {
		ltie7  : $.browser.msie && $.browser.version < 7,
		filter : function(src) {
			return "progid:DXImageTransform.Microsoft.AlphaImageLoader(enabled=true,sizingMethod=crop,src='"+src+"')";
		}
	};
	
	/**
	 * Applies ie png hack to selected dom elements
	 *
	 * $('img[@src$=.png]').ifixpng();
	 * @desc apply hack to all images with png extensions
	 *
	 * $('#panel, img[@src$=.png]').ifixpng();
	 * @desc apply hack to element #panel and all images with png extensions
	 *
	 * @name ifixpng
	 */
	 
	$.fn.ifixpng = hack.ltie7 ? function() {
    	return this.each(function() {
			var $$ = $(this);
			// in case rewriting urls
			var base = $('base').attr('href');
			if (base) {
				// remove anything after the last '/'
				base = base.replace(/\/[^\/]+$/,'/');
			}
			if ($$.is('img') || $$.is('input')) { // hack image tags present in dom
				if ($$.attr('src')) {
					if ($$.attr('src').match(/.*\.png([?].*)?$/i)) { // make sure it is png image
						// use source tag value if set 
						var source = (base && $$.attr('src').search(/^(\/|http:)/i)) ? base + $$.attr('src') : $$.attr('src');
						
						// apply filter
						$$.css({filter:hack.filter(source), width:$$.get(0).offsetWidth, height:$$.get(0).offsetHeight})
						  .attr({src:$.ifixpng.getPixel()})
						  .positionFix();
					}
				}
			} else { // hack png css properties present inside css
				var image = $$.css('backgroundImage');
				if (image.match(/^url\(["']?(.*\.png([?].*)?)["']?\)$/i)) {
          image = RegExp.$1;
					image = (base && image.substring(0,1)!='/') ? base + image : image;
					$$.css({backgroundImage:'none', filter:hack.filter(image)})
					  .children().children().positionFix();
				}
			}
		});
	} : function() { return this; };
	
	/**
	 * Removes any png hack that may have been applied previously
	 *
	 * $('img[@src$=.png]').iunfixpng();
	 * @desc revert hack on all images with png extensions
	 *
	 * $('#panel, img[@src$=.png]').iunfixpng();
	 * @desc revert hack on element #panel and all images with png extensions
	 *
	 * @name iunfixpng
	 */
	 
	$.fn.iunfixpng = hack.ltie7 ? function() {
    	return this.each(function() {
			var $$ = $(this);
			var src = $$.css('filter');
			if (src.match(/src=["']?(.*\.png([?].*)?)["']?/i)) { // get img source from filter
				src = RegExp.$1;
				if ($$.is('img') || $$.is('input')) {
					$$.attr({src:src}).css({filter:''});
				} else {
					$$.css({filter:'', background:'url('+src+')'});
				}
			}
		});
	} : function() { return this; };
	
	/**
	 * positions selected item relatively
	 */
	 
	$.fn.positionFix = function() {
		return this.each(function() {
			var $$ = $(this);
			var position = $$.css('position');
			if (position != 'absolute' && position != 'relative') {
				$$.css({position:'relative'});
			}
		});
	};

})(jQuery);