<!DOCTYPE html>
<a href="#">test</a>
<script src="http://code.jquery.com/jquery-latest.min.js"></script>
<script>
(function(){
var busy = false;
$('a').click(function (){
if (busy)
return;
busy = true;
setTimeout(function(){
alert(1);
busy = false;
},5000);
});
})();
</script>