Automating contrast accessibility

contrast.js

function AccessibleColor(el) {
	var backgroundRGB = el.css("backgroundColor");
	backgroundRGB = backgroundRGB.substring(backgroundRGB.length - 1, 4).replace(/\s/g, "").split(",");

	var sum = Math.round((
		(parseInt(backgroundRGB[0]) * 299) + 
		(parseInt(backgroundRGB[1]) * 587) + 
		(parseInt(backgroundRGB[2]) * 114)) / 1000);

	if (sum > 128) {
		el.style.color = "black";
	} else {
		el.style.color = "white";
	}
}