function rgb2hex(str) {
    // find all decimal color strings
    var matcher = str.match(/rgb\([0-9 ]+,[0-9 ]+,[0-9 ]+\)/gi);
    if(matcher) {
        for(var j=0; j < matcher.length; j++) {
            var regex = eval("/" + str2regex(matcher[j]) + "/gi");
            // replace the decimal color strings with hex color strings
            str = str.replace(regex, "#" + toHexColor(matcher[j]));
        }
    }
    return str;
}

function str2regex(string) {
    string = string.replace(/\//gi, "\\/");
    string = string.replace(/\(/gi, "\\(");
    string = string.replace(/\)/gi, "\\)");
    string = string.replace(/\[/gi, "\\[");
    string = string.replace(/\]/gi, "\\]");
    string = string.replace(/\+/gi, "\\+");
    string = string.replace(/\$/gi, "\\$");
    string = string.replace(/\*/gi, "\\*");
    string = string.replace(/\?/gi, "\\?");
    string = string.replace(/\^/gi, "\\^");
    string = string.replace(/\\b/gi, "\\\\b");
    string = string.replace(/\\B/gi, "\\\\B");
    string = string.replace(/\\d/gi, "\\\\d");
    string = string.replace(/\\B/gi, "\\\\B");
    string = string.replace(/\\D/gi, "\\\\D");
    string = string.replace(/\\f/gi, "\\\\f");
    string = string.replace(/\\n/gi, "\\\\n");
    string = string.replace(/\\r/gi, "\\\\r");
    string = string.replace(/\\t/gi, "\\\\t");
    string = string.replace(/\\v/gi, "\\\\v");
    string = string.replace(/\\s/gi, "\\\\s");
    string = string.replace(/\\S/gi, "\\\\S");
    string = string.replace(/\\w/gi, "\\\\w");
    string = string.replace(/\\W/gi, "\\\\W");
        
    return string;            
}

function toHexColor(color) {
    color = color.replace(/^rgb/g,'');
    color = color.replace(/\(/g,'');
    color = color.replace(/\)/g,'');
    color = color.replace(/ /g,'');
    color = color.split(',');
    var r = parseFloat(color[0]).toString(16).toUpperCase();
    var g = parseFloat(color[1]).toString(16).toUpperCase();
    var b = parseFloat(color[2]).toString(16).toUpperCase();
    if (r.length<2) { r='0'+r; }
    if (g.length<2) { g='0'+g; }
    if (b.length<2) { b='0'+b; }
    return r + g + b;
}