Cordova,backbone.js

Thank you Rahat Khanna  this is my code , iused  
 var username = document.getElementById('username').value;
 var password = document.getElementById('password').value;

but no luck, Thanks for helping me.

directory.views.SearchPage = Backbone.View.extend({


    initialize: function() {
        this.template = _.template(directory.utils.templateLoader.get('index1'));
    },


    render: function (eventName) {


       $(this.el).html(this.template(this.model.toJSON()));
       this.listView = new directory.views.EmployeeListView({ el: $('.textbox', this.el), model: this.model });
        this.listView.render();
        return this;
    },
    events: {
        "click #btnlogin": "Login"
    },
    Login: function (event) {
       
        debugger;
        var define = $('.textbox').val();
       // var username = $("#username").val();
     //   var password = $("#password").val();
        var username = document.getElementById('username').value;
        var password = document.getElementById('password').value;
        if (username == "" ||password == "") {
            //e.stopImmediatePropagation();
            event.stopPropagation();
            alert("Enter UserId/Password");
        }
        else {
            alert(define);
            //alert('http://?' + 'login_name=' + username + '&password=' + password);
            debugger;
            $.ajax({
                url: 'http://?' + 'login_name=' + username + '&password=' + password,
           
                async: false,
                type: "GET",
                success: function (data) {


                    //if (data.ContactId!=null) {
                    //alert(data.ResponseId);
                    // alert("Login Successfull.");
                    if (data.ResponseId == "0") {
                        alert("Login successful.");
                        window.location.href = "#Login";
                        // ClearDetais();
                        _isValidateLogin = true;
                        localStorage = {
                            setItem: function (key, value) { },
                            getItem: function (key) { return null; }
                        };
                        localStorage.setItem("ICName", JSON.stringify(data.ResponseId));
                        localStorage.setItem("ICID", data.ICID);
                        localStorage.setItem("IAID", data.IAID);
                        localStorage.setItem("ialastname", data.ialastname);
                        localStorage.setItem("iafirstname", data.iafirstname);
                        localStorage.setItem("IAPhone", data.IAPhone);
                        localStorage.setItem("IAEmail", data.IAEmail);
                        localStorage.fax("fax", data.fax);
                        // alert(localStorage.getItem("ICName"));
                    }
                    else {
                        // ClearDetais();
                        alert("Wrong EmailID/Password");
                        this.off();


                    }
                    //    LoginDetails = "";
                    //}
                }
            });
        }

The method which you have used is correct. You are using jQuery $('') to get the content from the html. My assumption for your script not working in the app on the device is that somehow the link to jquery script might not be working in your app. 

You have to check once again that you are not using a CDN link but referencing a local jQuery Library and try again. If this does not solve your problem, then you can use native javascript to get the values. For Ex:

var Loginname = document.getElementById('username').value;
var Password = document.getElementById('password').value;

If this also does not work, please upload your index.html source code. I will debug it and let you know.