;(function($) {

	var self, options,

	defaultOptions = {
		speed: 500
	}

	grayscale = function(src){
		var canvas = document.createElement('canvas');
		var ctx = canvas.getContext('2d');
		var imgObj = new Image();
		imgObj.src = src;
		canvas.width = imgObj.width;
		canvas.height = imgObj.height;
		ctx.drawImage(imgObj, 0, 0);
		var imgPixels = ctx.getImageData(0, 0, canvas.width, canvas.height);
		for(var y = 0; y < imgPixels.height; y++){
			for(var x = 0; x < imgPixels.width; x++){
				var i = (y * 4) * imgPixels.width + x * 4;
				var avg = (imgPixels.data[i] + imgPixels.data[i + 1] + imgPixels.data[i + 2]) / 3;
				imgPixels.data[i] = avg;
				imgPixels.data[i + 1] = avg;
				imgPixels.data[i + 2] = avg;
			}
		}
		ctx.putImageData(imgPixels, 0, 0, 0, 0, imgPixels.width, imgPixels.height);
		return canvas.toDataURL();
    };

	$.fn.nbGrayscale = function(opts) {


		if (!($.browser.msie && $.browser.version.slice(0,1) < '9') ) {


			self = $(this);
			options = $.extend({}, defaultOptions, opts);

			self.each(function() {
				$(this).css('opacity', 0);
			});

			$(window).load(function() {

				self.each(function(){

					var el = $(this);

					el.css({"position":"absolute"}).wrap("<div class='img_wrapper' style='display: inline-block'>").clone().addClass('img_grayscale').css({"position":"absolute","z-index":"998","opacity":"0"}).insertBefore(el).queue(function(){
						var el = $(this);
						el.parent().css({"width":this.width,"height":this.height});
						el.dequeue();
					});

					this.src = grayscale(this.src);

					el.animate({opacity:1}, options.speed);

					el.parent().mouseover(function(){
						el.parent().find('img:first').stop().animate({opacity:1}, options.speed);
					});
					el.parent().mouseout(function(){
						el.parent().find('img:first').stop().animate({opacity:0}, options.speed);
					});
				});


			});
		}
	};

})(jQuery);