listening login form

InjectJsWebview.kt

        web.settings.javaScriptEnabled = true
        web.settings.allowFileAccessFromFileURLs = true
        web.webViewClient = object: WebViewClient(){

            override fun onPageFinished(view: WebView?, url: String?) {
                super.onPageFinished(view, url)
                evaluateJS(view)
        }}

        web?.addJavascriptInterface(this, "LISTEN")
        web.loadUrl("☆url☆")

    }

    fun evaluateJS(web: WebView?){
        var function = """
            (function () {
                document.getElementsByClassName('btn btn-primary')[0].addEventListener('click', function(){
                        var empID = document.getElementById('empID').value;
                        var pass = document.getElementById('Password').value;
                        LISTEN.action(empID + '<==>'+ pass);
                    })
            })()
            """
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            web?.evaluateJavascript(function) { }
        }

    }

    @JavascriptInterface
    fun action(str: String) {
       Log.d("==>", str)
    }