Create a template to scan a barcode using zxing and return the data as payload

HI!
I try to build a ui_template to scan a barcode by unsing zxing under android and return the bar code as payload.
The free zxing tool is installed and working fine.

Here is my template so far:

<script type="text/javascript">

    if(window.location.hash.substr(1,2) == "zx"){
        var bc = window.location.hash.substr(3);
        localStorage["barcode"] = decodeURI(window.location.hash.substr(3))
        window.close();
        self.close();
        window.location.href = "about:blank";//In case self.close isn't allowed
    }
</script>
<SCRIPT type="text/javascript" >
    var changingHash = false;
    function onbarcode(event){

        switch(event.type){
            case "hashchange":{
                if(changingHash == true){
                    return;
                }
                var hash = window.location.hash;
                if(hash.substr(0,3) == "#zx"){
                    hash = window.location.hash.substr(3);
                    changingHash = true;
                    window.location.hash = event.oldURL.split("\#")[1] || ""
                    changingHash = false;
                    processBarcode(hash);
                }

                break;
            }
            case "storage":{
                window.focus();
                if(event.key == "barcode"){
                    window.removeEventListener("storage", onbarcode, false);
                    processBarcode(event.newValue);
                }
                break;
            }
            default:{
                console.log(event)
                break;
            }
        }
    }
    window.addEventListener("hashchange", onbarcode, false);

function getScan(){
    
        var href = window.location.href;
        var ptr = href.lastIndexOf("#");
        if(ptr>0){
            href = href.substr(0,ptr);
        }
        window.addEventListener("storage", onbarcode, false);
        setTimeout('window.removeEventListener("storage", onbarcode, false)', 15000);
        localStorage.removeItem("barcode");
        //window.open  (href + "#zx" + new Date().toString());

       if(navigator.userAgent.match(/Firefox/i)){
           //Used for Firefox. If Chrome uses this, it raises the "hashchanged" event only.
            window.location.href =  ("zxing://scan/?ret=" + encodeURIComponent(href + "#zx{CODE}"));
        }else{
            //Used for Chrome. If Firefox uses this, it leaves the scan window open.
            window.open   ("zxing://scan/?ret=" + encodeURIComponent(href + "#zx{CODE}"));
        }
    }

    function processBarcode(bc){
        document.getElementById("scans").innerHTML += "<div>" + bc + "</div>";
        //put your code in place of the line above.
    }

</SCRIPT>


<md-button onclick="getScan();">
    Barcode
</md-button>

Most of the code is just a copy form the zying help page and it is working fine. After pushing the button the tools opens up and I'm able to scan.
But how to manage to get the data back to the Node-RED Server as payload?
The final data are available as "bc" in the processBarcode() function, this is confirmed. This function is trigger by event after the scan tool is finished. How to make the payload send?