         let b = Int(255.0 * blue)
 
         let str = NSString(format: "#%02x%02x%02x", r, g, b)
-        return str
+        return str as String
     }
 
     /**

        runJS("RE.setFontSize('\(size))px');")
    }
    
    public func setBackgroundColor(color: UIColor) {
        let hex = colorToHex(color)
        runJS("RE.setBackgroundColor('\(hex)');")
    }

        let callbackPrefix = "re-callback://"
        let prefixRange = callbackPrefix.startIndex..<callbackPrefix.endIndex
        
        if request.URL?.absoluteString?.hasPrefix(callbackPrefix) == true {
            if let method = request.URL?.absoluteString?.stringByReplacingCharactersInRange(prefixRange, withString: "") {
                
                if method.hasPrefix("input") {
                    let content = runJS("RE.getHtml()")
