title: Slowdown ajax requests for keyup-event of a text-field
body: <p><code>#target</code> is a input text field. As the user types something into it, I want to check via an ajax request (function <code>ajaxSend</code>), if the value is correct. I want to slow down the ajax-check a little bit, as if somebody is typing very fast I do not have to check for each keyup, but i.e. for each 500ms.</p>
  
  <p>The inout field is created dynamically, that's why I have to delegate the keyup event.</p>
  
  <p>I don't know, what I'm doing wrong, but there are still multiple requests for each keyup:</p>
  
  <pre><code>$('body').off('keyup', '#target').on('keyup', '#target', function() { 
      var value = $(this).val();
      if (value) setTimeout( ajaxSend(value), 500 );
  });
  </code></pre>