Your running = false;
should be inside timeout function, as timeout will execute asyncronically, the running = false;
will execute before your timeout ends
A simple example would be
var running = false,
div = document.getElementById('response'),
limit = 5,
current = 0;
$('#trigger').click(function () {
if (running === true) {
alert('Error: The cycle was running. Aborting.');
running = false;
return false;
}
running = true;
var end = setInterval(function () {
if (current >= limit || running == false) {
running = false;
clearInterval(end);
}
div.innerHTML += 'Hello World<br />';
current++;
}, 500);
});