Basic absolute conversions in javascript. Converts a subset of 'http://www.w3.org/TR/css3-values/' in pure javascript. Returns linear measurements in pixels and angles in degrees (perhaps this should be rads...)

parseUnit

var ppi = 96 * window.devicePixelRatio || 1; // 96 = CSS DPI/PPI reference measurement
var absoluteMeasurements = {
	px : 1,
	pt : 4 / 3,
	pc : 12 * (4 / 3),
	in : ppi,
	cm : ppi / 2.54,
	mm : ppi / 25.4,
	deg: 1,
	grad: 400 / 360,
	rad: 180 / Math.PI,
	turn: 360
};

function parseUnit(value) {
	var triple = value.match(/([\d|\.]+)(\D*)/);

	return (triple.length !== 3) ? NaN
		: absoluteMeasurements[(triple[2] || '').toLowerCase()] * (+triple[1] || 0);
}