jQuery check on wordchange rather than "change" trigger

I have a input that the user types a search parameter into, at the moment i have it on keyup to do a POST ajax request to a PHP script that returns search results. however its firing off 50 billion (not literally) post requests in about 10 seconds (as the user types) 开发者_StackOverflow中文版which slows the whole experience down. Can i use jQuery to detect a "wordup" rather than "keyup" by detecting the use of the space bar?

Does this make sense?

I'm adding this as a separate answer, because it's entirely different to my first answer.

$('#yourinput').keyup(function(){
    var input = this,
        timer = $.data(this, 'timer'),
        lastrequest = $.data(this, 'lastrequest');

    if (timer) { // if there is a keyup timeout still pending, cancel it
        clearTimeout(timer);
        $.data(this, 'timer', 0);
    }

    if (lastrequest) { // if there is an AJAX request still running, abort it
        lastrequest.abort();
        $.data(this, 'lastrequest', false);
    }

    timer = setTimeout(function(){
        lastrequest = $.post({ // or whatever your AJAX call is...
            url: 'yourfile',
            data: { search: input.value },
            success: function(response){
                lastrequest = false;
                // handle response here
            }
        });
        $.data(input, 'lastrequest', lastrequest);
    }, 500);
    $.data(this, 'timer', timer);
});

$('#yourinput').keyup(function(e) {
    if (e.which == 32) { // space key pressed
        // do your AJAX here
    }
});

See event.which for more information about this feature.

You certainly could; you detect the keyup events locally and check them for space.

But you'll get a lot more leverage if you can contrive to get all the search results that match a prefix and send them down to the javascript in a data structure. Have a look at "digital search trees" (also known as "tries") for details.

You could use something like a delay for when the user has stopped typing for a specific period of time?

Perhaps something like this? You could add the additional function to trigger a space bar press as well. (This was used just for a Google-Style insta-search, so it may / may not help).

$('#Search').keyup(function (event) 
        {
            delay(function(){

            var textboxValue = $('#Search').val();

            if( textboxValue.length >= 2)
            {
              //Perform search
            }

        });
});

var delay = (function(){
var timer = 0;
    return function(callback, ms){
    clearTimeout (timer);
    timer = setTimeout(callback, ms);
};
})();