javascript - Which is the correct way to check if a session is still running? Which are some ways? -

so have had first experience web design, there things did in way didn't like, because of time. anyway, don't know correct way handle sessions. did in previous project embed php html , based on whatever in $_session, id , user type number, i'd open or close parts of website user, through embedded php.

however, not how wanted initially, @ first wanted make javascript code send request through ajax server, , check if session still active, , based on open/close parts of website, i'd have make request on every page , every make sure user logged in. should handle client-side?

what other ways check session without embedding php , using javascript instead modify html document.

to this, need ajax request on loop , php file check session.

the javascript

function checklogin(un) { //put function in loop of sort depending on how want use   var xmlhttp = new xmlhttprequest();   xmlhttp.onreadystatechange = function() {     if (xmlhttp.readystate == 4 && xmlhttp.status == 200) {       logout(xmlhttp.responsetext);     }   }   xmlhttp.open("get", "checklogin.php?un=" + un, true);   xmlhttp.send(); }  function logout(resp) {   if (resp == "false") { //comparing actual text, not boolean     window.location.href = 'logout.php'; //destroy session or   } } 

the php file checklogin.php (very simple)

<?php if ($_session[$_get['un']] != true) {   echo 'false'; } ?> 

the php depend on how store sessions, in case using 1 session titled username stores true if signed in. recommend making more complex if decide use it.