Optimised search using Ajax and keypress

Question

I have the following code that I want to use to search a database as a user is typing into a textbox. The code below works fine but it seems a little inefficient, as if a user is typing really fast. I am potentially doing many more searches than necessary. So if a user is typing in "sailing", I am searching on "sail", "saili", "sailin", and "sailing".

I wanted to see if there was a way to detect any particular time between keypresses so only search if user stops typing for 500 milliseconds or something like this.

Is there a best practice for something like this?

$('#searchString').keypress(function(e) {

    if (e.keyCode == 13) {

        var url = '/Tracker/Search/' + $("#searchString").val();
        $.get(url, function(data) {
            $('div#results').html(data);
            $('#results').show();
        });
    }
    else {

        var existingString = $("#searchString").val();
        if (existingString.length > 2) {
            var url = '/Tracker/Search/' + existingString;
            $.get(url, function(data) {
                $('div#results').html(data);
                $('#results').show();
            });
        }
    }

Answer 1

You can do something like this:

$('#searchString').keyup(function(e) {
    clearTimeout($.data(this, 'timer'));
    if (e.keyCode == 13)
      search(true);
    else
      $(this).data('timer', setTimeout(search, 500));
});
function search(force) {
    var existingString = $("#searchString").val();
    if (!force && existingString.length < 3) return; //wasn't enter, not > 2 char
    $.get('/Tracker/Search/' + existingString, function(data) {
        $('div#results').html(data);
        $('#results').show();
    });
}

What this does is perform a search (on keyup, better than keypress for these situations) after 500ms by storing a timer on the #searchString element's .data() collection. Every keyup it clears that timer, and if the key was enter, searches immediately, if it wasn't sets a another 500ms timeout before auto-searching.