var idleTime    = 5000;     // in milliseconds (5 seconds)
var timeOut     ='';

function initIdleTimer() {
    
    Event.observe(document.body, 'keypress', resetIdle, true);
    Event.observe(document.body, 'mouseup', resetIdle, true);
    
    var obj = document.getElementById( GetMasterClientId('hdnTimeoutIdleSec') );
    idleTime = obj.value * 1000;
    
    //alert(idleTime);
    
    setIdle();
    
}

function onIdleFunction(){
    
    var obj = document.getElementById( GetMasterClientId('hdnTimeout') );
    obj.value = "timeout";
    if (typeof theForm != 'undefined')
    {
        theForm.submit();
    }
}

function resetIdle(){
    
    //alert('resetIdle');
    window.clearTimeout( timeOut );
    setIdle();
    
}

function setIdle(){
    
    timeOut = window.setTimeout( "onIdleFunction()", idleTime );
    
}

Event.observe(window, 'load', initIdleTimer, false);