javascript - can't login to facebook with parse -

i'm trying add facebook login option website , want login parse account.

i've added followed scripts:

1) after tag inside index.html:

<script>   // initialize parse   parse.initialize("**********************", "*****************************");        window.fbasyncinit = function() {     parse.facebookutils.init({ // line replaces fb.init({       appid      : '{******************}', // facebook app id       status     : true,  // check facebook login status       cookie     : true,  // enable cookies allow parse access session       xfbml      : true,  // initialize facebook social plugins on page       version    : 'v2.3' // point latest facebook graph api version     });          // run code after facebook sdk loaded.    };        (function(d, s, id){     var js, fjs = d.getelementsbytagname(s)[0];     if (d.getelementbyid(id)) {return;}     js = d.createelement(s); js.id = id;     js.src = "//connect.facebook.net/en_us/sdk.js";     fjs.parentnode.insertbefore(js, fjs);   }(document, 'script', 'facebook-jssdk')); </script> 

2)log in function inside login.js:

function loginwithfacebook(){  parse.facebookutils.login(null, {   success: function(user) {     if (!user.existed()) {       alert("user signed , logged in through facebook!");     } else {       alert("user logged in through facebook!");     }   },   error: function(user, error) {     alert("user cancelled facebook login or did not authorize.");   } }); } 

and of course 2 lines in tag in index.html:

<script src="//www.parsecdn.com/js/parse-1.4.2.min.js"></script> <script src='login.js'></script> 

3) , have simple tag have onclick attribute:

<a href="#" onclick="loginwithfacebook();">log in</a> 

however, when click on it, nothing happens, none of messages inside loginwithfacebook function appears. in face, none of messages inside parse.facebookutils.login appears, cause when alert message before call parse.facebookutils.login appears...