rgb to Hex

//StackOverflow:
//http://stackoverflow.com/questions/5623838/rgb-to-hex-and-hex-to-rgb

//Solution 1.
//////////////////////////////////////////////
function rgbToHex(r, g, b) {
    return "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);
}
//////////////////////////////////////////////

//Solution 2.
//////////////////////////////////////////////
function hexToRgb(hex) {
    var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
    return result ? {
        r: parseInt(result[1], 16),
        g: parseInt(result[2], 16),
        b: parseInt(result[3], 16)
    } : null;
}

alert( hexToRgb("#0033ff").g ); // "51";
//////////////////////////////////////////////

//Solution 3.
//////////////////////////////////////////////
function rgbToHex(R,G,B) {return toHex(R)+toHex(G)+toHex(B)}
function toHex(n) {
 n = parseInt(n,10);
 if (isNaN(n)) return "00";
 n = Math.max(0,Math.min(n,255));
 return "0123456789ABCDEF".charAt((n-n%16)/16)
      + "0123456789ABCDEF".charAt(n%16);
}

///////////////////////////////////////////////

//solution 3.
//////////////////////////////////////////////
function componentToHex(c) {
    var hex = c.toString(16);
    return hex.length == 1 ? "0" + hex : hex;
}

function rgbToHex(r, g, b) {
    return "#" + componentToHex(r) + componentToHex(g) + componentToHex(b);
}

alert( rgbToHex(0, 51, 255) ); // #0033ff
//////////////////////////////////////////////

//Solution 4. by Carlos
//Convert RGB Values in Hexadecimal color
		//R:Number [0-255], G:Number [0-255], B:Number [0-255]
		//return Hexagecimal String with the hash. ex: '#ff0000'
		function rgb_to_hex (R, G, B){

			//[0-9] 10  11  12  13  14  15
			//[0-9] A   B   C   D   E   F	

			function toLetters (arg){
				return ['a', 'b', 'c', 'd', 'e', 'f'].find(function (el, i, arr) {
					if (arg === i+10) return el
				})
			}

			// 255 -> 15
			//  x  ->  ?
			//? = x*15/255

			R = Math.round((Math.abs(R)*15)/255);
			R = (R>9) ? toLetters(R):R;

			G = Math.round((Math.abs(G)*15)/255);
			G = (G>9) ? toLetters(G):G;

			B = Math.round((Math.abs(B)*15)/255);
			B = (B>9) ? toLetters(B):B;

			return '#'+R+R+G+G+B+B;
		}

		alert.log(rgb_to_hex(255,255,20));