java - page not redirecting after session expires -

i have done simple page move page when session expires. have set time 50 seconds , after move page unfortunately not moving , helpless know wrong. grateful if please solve problem

function x(){        var timeout =<%=session.getattribute("login")%>;  var checktimeout;  checktimeout = function(){     if(timeout==null || timeout==""){         window.location.replace("failedsession.jsp"); //document.getelementbyid("b").innerhtml="session timed out";         // redirect timeout page     }else{           window.settimeout(checktimeout, 1000); // check once per second     }} checktimeout(); // insert checktimeout function when call x(), execute in end. } 

the problem code:

nowhere in code, calling checktimeout();. why not being executed. should have checked execution of function putting alert inside function. during body onload @rgeorge has suggested.

note: logic looks alright. have habit of putting semicolons after javascript statements @mark has suggested.

answer updated:

1) don't use function name , variable name same. ex: x. have names unique. conflicting.

2) x greater lastactivity + timeout because x not increasing (7 > 1+1). means else condition never execute. means checktimeout never called.

3) function checktimeout() never execute because never called anywhere. executing x(). not sufficient call checktimeout().

answer updated:

do this:

<script type="text/javascript"> function x(){        var timeout =1; var lastactivity = 1; var x=7;  var checktimeout;  checktimeout = function(){     if(x > lastactivity + timeout){ document.getelementbyid("b").innerhtml=x;         // redirect timeout page     }else{         window.settimeout(checktimeout, 1000); // check once per second     }} checktimeout(); // insert checktimeout function when call x(), execute in end. }      </script> 

your code works fine me. div value changes 7. , code >> http://jsfiddle.net/hmhp9/