Get text from field on keyup, but with delay for further typing

Sorry i haven't tested this and it's a bit off the top of my head, but something along these lines should hopefully do the trick. Change the 2000 to however many milliseconds you need between server posts

<input type="text" id="mytextbox" style="border: 1px solid" />
<span></span>

<script language="javascript" type="text/javascript">
    jQuery(function(){
      jQuery('#mytextbox')
        .data('timeout', null)
        .keyup(function(){
            clearTimeout(jQuery(this).data('timeout'));
            jQuery(this).data('timeout', setTimeout(submitQuizForm, 2000));
        });
    });
</script>

Here's your fancy jquery extension:

(function($){

$.widget("ui.onDelayedKeyup", {

    _init : function() {
        var self = this;
        $(this.element).keyup(function() {
            if(typeof(window['inputTimeout']) != "undefined"){
                window.clearTimeout(inputTimeout);
            }  
            var handler = self.options.handler;
            window['inputTimeout'] = window.setTimeout(function() {
                handler.call(self.element) }, self.options.delay);
        });
    },
    options: {
        handler: $.noop(),
        delay: 500
    }

});
})(jQuery);

Use it like so:

    $("input.filterField").onDelayedKeyup({
        handler: function() {
            if ($.trim($(this).val()).length > 0) {
                //reload my data store using the filter string.
            }
        }
    });

Does a half-second delay by default.

As an update, i ended up with this which seems to work well:

function afterDelayedKeyup(selector, action, delay){
  jQuery(selector).keyup(function(){
    if(typeof(window['inputTimeout']) != "undefined"){
      clearTimeout(inputTimeout);
    }  
    inputTimeout = setTimeout(action, delay);
  });
}

I then call this from the page in question's document.ready block with

  afterDelayedKeyup('input#search',"submitQuizForm()",500)

What would be nice would be to make a new jquery event which uses this logic, eg .delayedKeyup to go alongside .keyup, so i could just say something like this for an individual page's document.ready block.

  jQuery('input#search').delayedKeyup(function(){
    submitQuizForm();
  });

But, i don't know how to customise jquery in this way. That's a nice homework task though.