This function returns a string containing the Hexadecimal color representation of RGB values.

function toHexColor(r,g,b)
{
 var hex='#';
 var hexStr = '0123456789ABCDEF';
 // R
 low = r % 16;
 high = (r - low)/16;
 hex+=hexStr.charAt(high) + hexStr.charAt(low);
 // G
 low = g % 16;
 high = (g - low)/16;
 hex+=hexStr.charAt(high) + hexStr.charAt(low);
 // B
 low = b % 16;
 high = (b - low)/16;
 hex+=hexStr.charAt(high) + hexStr.charAt(low);
 return hex;
}