function grayscale(image) {
	var imgObj = $(image).get(0);
	if (! imgObj) return;

	$(image).attr("orig", $(image).attr("src"));

	if($.browser.msie){
		grayscaleImageIE(imgObj);
	} else {
		imgObj.src = grayscaleImage(imgObj);
	}
}

function resetImage(image) {
	var imgObj = $(image).get(0);
	if (! imgObj) return;

	if($.browser.msie){
		resetImageIE(imgObj);
	} else {
		imgObj.src = $(image).attr("orig");
	}
}


function grayscaleImageIE(imgObj)
{
	imgObj.style.filter = 'progid:DXImageTransform.Microsoft.BasicImage(grayScale=1)';
}

function resetImageIE(imgObj)
{
	imgObj.style.filter = '';
}

function grayscaleImage(imgObj)
{
	var canvas = document.createElement('canvas');
	var canvasContext = canvas.getContext('2d');

	var imgW = imgObj.width;
	var imgH = imgObj.height;
	canvas.width = imgW;
	canvas.height = imgH;

	canvasContext.drawImage(imgObj, 0, 0);
	var imgPixels = canvasContext.getImageData(0, 0, imgW, imgH);

	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;
		}
	}

	canvasContext.putImageData(imgPixels, 0, 0, 0, 0, imgPixels.width, imgPixels.height);
	return canvas.toDataURL();
}