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Run javascript function when user finishes typing instead of on key up?


Question

I want to trigger an ajax request when the user has finished typing in a text box. I don't want it to run the function on every time the user types a letter because that would result in A LOT of ajax requests, however I don't want them to have to hit the enter button either.

Is there a way so I can detect when the user has finished typing and then do the ajax request?

Using jQuery here! Dave

2010/11/18
1
485
11/18/2010 10:13:04 PM

Accepted Answer

So, I'm going to guess finish typing means you just stop for a while, say 5 seconds. So with that in mind, lets start a timer when the user releases a key and clear it when they press one. I decided the input in question will be #myInput.

Making a few assumptions...

//setup before functions
var typingTimer;                //timer identifier
var doneTypingInterval = 5000;  //time in ms, 5 second for example
var $input = $('#myInput');

//on keyup, start the countdown
$input.on('keyup', function () {
  clearTimeout(typingTimer);
  typingTimer = setTimeout(doneTyping, doneTypingInterval);
});

//on keydown, clear the countdown 
$input.on('keydown', function () {
  clearTimeout(typingTimer);
});

//user is "finished typing," do something
function doneTyping () {
  //do something
}
2015/07/16
707
7/16/2015 8:32:41 PM


It's just one line with underscore.js debounce function:

$('#my-input-box').keyup(_.debounce(doSomething , 500));

This basically says doSomething 500 milliseconds after I stop typing.

For more info: http://underscorejs.org/#debounce

2016/04/13

Yes, you can set a timeout of say 2 seconds on each and every key up event which will fire an ajax request. You can also store the XHR method and abort it on subsequent key press events so that you save bandwith even more. Here's something I've written for an autocomplete script of mine.

var timer;
var x;

$(".some-input").keyup(function () {
    if (x) { x.abort() } // If there is an existing XHR, abort it.
    clearTimeout(timer); // Clear the timer so we don't end up with dupes.
    timer = setTimeout(function() { // assign timer a new timeout 
        x = $.getJSON(...); // run ajax request and store in x variable (so we can cancel)
    }, 2000); // 2000ms delay, tweak for faster/slower
});

Hope this helps,

Marko

2010/11/18

var timer;
var timeout = 1000;

$('#in').keyup(function(){
    clearTimeout(timer);
    if ($('#in').val) {
        timer = setTimeout(function(){
            //do stuff here e.g ajax call etc....
             var v = $("#in").val();
             $("#out").html(v);
        }, timeout);
    }
});

full example here: http://jsfiddle.net/ZYXp4/8/

2012/08/14

Both top 2 answers doesn't work for me. So, here is my solution:

var timeout = null;

$('#myInput').keyup(function() {
    clearTimeout(timeout);

    timeout = setTimeout(function() {
        //do stuff here
    }, 500);
});
2018/02/08

Late answer but I'm adding it because it's 2019 and this is entirely achievable using pretty ES6, no third party libraries, and I find most of the highly rated answers are bulky and weighed down with too many variables.

Elegant solution taken from this excellent blog post.

function debounce(callback, wait) {
  let timeout;
  return (...args) => {
      clearTimeout(timeout);
      timeout = setTimeout(function () { callback.apply(this, args) }, wait);
  };
}

window.addEventListener('keyup', debounce( () => {
    // code you would like to run 1000ms after the keyup event has stopped firing
    // further keyup events reset the timer, as expected
}, 1000))
2020/07/30

Source: https://stackoverflow.com/questions/4220126
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