javascript - On click of button, check if user is logged in or not -

i have button responsible performing multiple task, , has lot of scripting it. when button

<button type="submit" value="submit" name="submit" class="second_button">negotiate</button> 

the script applied on button

<script>  var startclock; var submitamt; var walkaway; var digits;  $(function() {   startclock = $('#startclock').on('click', onstart);   submitamt = $('#submitamt').on('click', onsubmit);   walkaway = $('#walkaway').on('click', onwalkaway);   digits = $('#count span');   beforestart(); });  var onstart = function(e) {   startclock.fadeout(function() {     starttimer();     submitamt.fadein(function() {       submitamt.trigger('click'); // fire click event on submit     });     walkaway.fadein();   }); };  var onsubmit = function(e) {   var txtbox = $('#txt').val();   var hiddentxt = $('#hidden').val();   $.ajax({     type: 'post',     url: 'test2.php',     datatype: 'json',     data: {       txt: txtbox,       hidden: hiddentxt     },     cache: false,     success: function(returndata) {           console.log(returndata[3]);     // $('#proddisplay').html(returndata);     },     error: function() {        console.error('failed process ajax !');     }   }); };  var onwalkaway = function(e) {   console.log('onwalkaway ...'); };  var counter; var timer; var starttimer = function() {   counter = 120;   timer = null;   timer = setinterval(ticker, 1000); };  var beforestart = function() {   digits.eq(0).text('2');   digits.eq(2).text('0');   digits.eq(3).text('0'); };  var ticker = function() {   counter--;   var t = (counter / 60) | 0; // round off   digits.eq(0).text(t);   t = ((counter % 60) / 10) | 0;   digits.eq(2).text(t);   t = (counter % 60) % 10;   digits.eq(3).text(t);   if (!counter) {     clearinterval(timer);     alert('time out !');     resetview();   } };  var resetview = function() {   walkaway.fadeout();   submitamt.fadeout(function() {     beforestart();     startclock.fadein();   }); }; </script> 

before script executes wish check if user logged in or not, in normal php use code

<? if (isset($_session['loggedin']) && $_session['loggedin'] == true || isset($_session['fb_logged_in']) && $_session['fb_logged_in'] == true )     {?>         <!--display message-->     <?}?>    

but not able understand how embed script wish display popup message if user not logged in , ask user login first

it not recommended check client side scripting. try hidden variable..

<input type="hidden" name="userlog" id="userlog" value="<?=$_session['fb_logged_in'];?>"> 

and in script check

if($('#userlog')!=''){     // something.. }