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function ColorLuminance(hex, lum) {

	// validate hex string
	hex = String(hex).replace(/[^0-9a-f]/gi, '');
	if (hex.length < 6) {
		hex = hex[0]+hex[0]+hex[1]+hex[1]+hex[2]+hex[2];
	}
	lum = lum || 0;

	// convert to decimal and change luminosity
	var rgb = "#", c, i;
	for (i = 0; i < 3; i++) {
		c = parseInt(hex.substr(i*2,2), 16);
		c = Math.round(Math.min(Math.max(0, c + (c * lum)), 255)).toString(16);
		rgb += ("00"+c).substr(c.length);
	}

	return rgb;
}

// http://www.sitepoint.com/javascript-generate-lighter-darker-color/
// http://stackoverflow.com/questions/1507931/generate-lighter-darker-color-in-css-using-javascript