Want to add a mobile number at sign up time

I have register.js file :

var dialogs = require("ui/dialogs");
var el = require("../shared/models/el");
var frameModule = require("ui/frame");
var images = require("../shared/utils/images");
var pageData = require("../shared/models/userCredentials");
var viewModule = require("ui/core/view");
exports.load = function (args) {
    var page = args.object;
    var email = viewModule.getViewById(page, "email");
    var username = viewModule.getViewById(page, "username");
    var mobile = viewModule.getViewById(page, "mobile");
    pageData.set("email_address", "");
    pageData.set("username", "");
    pageData.set("password", "");
    pageData.set("mobile", "");
    pageData.set("logoSource", images.logo);
    page.bindingContext = pageData;
    // Turn off autocorrect and autocapitalization for iOS
    if (username.ios) {
        email.ios.autocapitalizationType =
            UITextAutocapitalizationType.UITextAutocapitalizationTypeNone;
        email.ios.autocorrectionType =
            UITextAutocorrectionType.UITextAutocorrectionTypeNo;
        username.ios.autocapitalizationType =
            UITextAutocapitalizationType.UITextAutocapitalizationTypeNone;
        username.ios.autocorrectionType =
            UITextAutocorrectionType.UITextAutocorrectionTypeNo;
    }
};
exports.register = function () {
    el.Users.register(
        pageData.get("username"),
        pageData.get("password"), {
            Email: pageData.get("email_address"),
            moblie: pageData.get("moblie")
        },
        
        function (response) {
            dialogs
                .alert("Your account was successfully created.")
                .then(function () {
                    frameModule.topmost().navigate("./views/login");
                });
        },
        function (error) {
            
            dialogs.alert({
                message:  "Unfortunately we were unable to create your account.",
                
                okButtonText: "OK"
            });
        }
    );
};

and written this in register.xml file

<Page loaded="load">
  <StackLayout>
      <Image source="{{ logoSource }}" />

      <Label text="Email Address:" />
      <TextField width="200" text="{{ email_address }}" id="email" hint="Email Address" keyboardType="email" />

      <Label text="Username:" />
      <TextField width="200" text="{{ username }}" id="username" hint="Username" />

      <Label text="Mobile No:" />
      <TextField width="200" text="{{ mobile }}" id="mobile"  hint="Mobile" keybordType="number" />
      
      <Label text="Password:" />
      <TextField width="200" text="{{ password }}" secure="true" hint="Password" />
      
      <Button text="Sign Up" tap="register" />
  </StackLayout>
</Page>

In the backend service I can see the usename and email address of the user but mobile number is not set. Guide me through this code.

Thanks

Manthan Shah