How to make a ajax filter in jquery?

I am trying to make a filtering where a user would search by last name. Right now I have it on keypress but of course this does too many ajax requests so I would rather have it after a few keys or something like that.

I am return all the results as a table(I have a partial view that generates a table with the info in it)

 $(function ()
    {
        $('#LastName').keypress(function ()
        {

            $.post('ActionMethod', { 'lastName': $(this).val() }, function (response)
            {
                $('#results').html(response);
            });
        });
    });
开发者_运维百科

Any ideas how I should do this. I guess the logic would be similar to a auto complete and I know they can set like how many keystrokes before you query db.

I think you should just use timeouts and delay the execution of the ajax call. If a keypress occurs before the execution then reset the timer...

$(function ()
    {
        var timer;
        $('#LastName').keypress(function ()
        {
            var _this = this; // we need to store the this to a variable since it will be called out of context from the timeout
            clearTimeout(timer);
            timer = setTimeout(function(){
                         $.post('ActionMethod', { 'lastName': $(_this).val() }, function (response)
                         {
                             $('#results').html(response);
                         });
                       }, 500); // delay for 500 milliseconds
        });
    });

How about something like...

$(function ()
{
    $('#LastName').keypress(function ()
    {
        if($(this).val().length > 4)
        {
            $.post('ActionMethod', { 'lastName': $(this).val() }, function (response)
            {
                 $('#results').html(response);
            });
        }
    });
});

You could pre-load all unique values for names beforehand, and work with that array. This works alright if you don't have too many values. For your case, I guess, I doubt there will be thousands or millions of unique last names...

You could also set a time limit between ajax requests, rather than the number of keystrokes. (Like Gaby suggested).

The jQuery throttle debounce plugin provides an easy way to handle rate-limiting.