How to convert rgb values into regular css color values?

I trying to compare the styles of elements on my page. But one element dynamically changes it's text color to red, but represented as a rgb value. And the other element (to compare it with) uses #123456 values. Is there a converter somewhere that can take rgb and turn it into #number?

For exa开发者_JAVA百科mple:

#000 instead of rgb(0, 0, 0)

People always forget that rgb colors can be expressed as percentages, as well as integers.

function rgbToHex(rgb){
    var i= 0, c, hex= '#',
    rgb= String(rgb).match(/\d+(\.\d+)?%?/g);
    while(i<3){
        c= rgb[i++];
        if(c.indexOf('%')!= -1){
            c= Math.round(parseFloat(c)*2.55);
        }
        c= (+c).toString(16);
        if(c.length== 1) c= '0'+c;
        hex+= c;
    }
    return hex;
}




alert(rgbtohex('rgb(255,127,0)')+'\n'+
rgbtohex('rgb(100%,50%,0)'));

/*  returned value: 
#ff7f00
#ff7f00
*/

// also works with arrays- rgbToHex([100,200,60])

// returned value: #64c83c

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);
}

edited. courtesy of http://www.javascripter.net/faq/rgbtohex.htm