颜色RGB转HEX

color-to-hex.js

String.prototype.colorHex = function() {
	
	var that = this;
	//十六进制颜色值的正则表达式
	var reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/;
	// 如果是rgb颜色表示
	if (/^(rgb|RGB)/.test(that)) {
		var aColor = that.replace(/(?:\(|\)|rgb|RGB)*/g, "").split(",");
		var strHex = "#";
		for (var i=0; i<aColor.length; i++) {
			var hex = Number(aColor[i]).toString(16);
			if (hex.length < 2) {
				hex = '0' + hex;    
			}
			strHex += hex;
		}
		if (strHex.length !== 7) {
			strHex = that;    
		}
		return strHex;
	} else if (reg.test(that)) {
		var aNum = that.replace(/#/,"").split("");
		if (aNum.length === 6) {
			return that;    
		} else if(aNum.length === 3) {
			var numHex = "#";
			for (var i=0; i<aNum.length; i+=1) {
				numHex += (aNum[i] + aNum[i]);
			}
			return numHex;
		}
	}
	return that;
};