On keypress, when stop after X seconds call function

Question

I have a text input and a textarea and I'm passing the value from the input to the textarea. I am trying to do, when you type something in the input and you stop, after 2 seconds show the values to the textarea.

In this example the textarea gets the input's value instantly:

http://jsfiddle.net/DXMG6/

So i want, when you type and stop, after 2 seconds give the value.

How can I achieve this? I tried to use setTimeout but when the 2 seconds pass, then it keeps getting the value instantly. So basically it works for the first 2 seconds.

Answer 1

You have to reset the timer everytime the user presses the key again:

jQuery(function($){

   function changeFn(){
      alert('Changed');
   } 


   var timer;

   $("#string").bind("keyup", function(){
      clearTimeout(timer);
      timer = setTimeout(changeFn, 2000)
   });

});

Answer 2

Once i made this plugin called bindDelay for jQuery:

$.fn.bindDelay = function( eventType, eventData, handler, timer ) {
    if ( $.isFunction(eventData) ) {
        timer = handler;
        handler = eventData;
    }
    timer = (typeof timer === "number") ? timer : 300;
    var timeouts;
    $(this).bind(eventType, function(event) {
        var that = this;
        clearTimeout(timeouts);
        timeouts = setTimeout(function() {
            handler.call(that, event);
        }, timer);
    });
};

Used like a normal bind method but the last argument is the delay before firing the handler (in mil sec):

 $("input").bindDelay('keyup', function() {
     $("textarea").text( $(this).val() );
 }, 2000);

See fiddle: http://jsfiddle.net/c82Ye/2/

And you unbind and trigger it like normal:

$("input").unbind("keyup");
$("input").trigger("keyup");

Answer 3

setTimeout returns an ID of the "job". what you have to do is to clearTimeout(id) every type and setTimeout again:

var tID = null;
onclick() {
    if (tID !== null) clearTimeout(tID);
    tID = setTimeout(function() { /*Do domething*/ }, 2000);
}

Answer 4

What you need to do is set a timeout, and save the resulting timeout id . Then you need to check if the timeout id has been saved at each keypress. If the timeout is set, clear the timeout and reset it. Something like this:

var timeoutId = null;
var myFunc = function() {
    timeoutId = null;
    // Do stuff
};
var myEventHandler = function() {
    if (timeoutId) {
        window.clearTimeout(timeoutId);
    }
    timeoutId = window.setTimeout(myFunc, 2000);
};

...or check the updated fiddle:

http://jsfiddle.net/DXMG6/5/

Answer 5

I've updated your fiddle

This will update the textarea value 2 seconds after you end editing the text.

The relevant part is this: we keep a reference to a timeout, when the keyup event is fired we clear the previous timeout and we start a new timeout, that will fire in 2 seconds.

var timeout = null;
$("#string").on("keyup keypress paste mouseup", function () {
    clearTimeout(timeout);
    timeout = setTimeout(function() {
        // ... your code here
    }, 2000);
});

Answer 6

Try something like this. Use setTimeout, but each time a key is pressed, reset the timer and start over...

http://jsfiddle.net/DXMG6/10/

var textTimer=null;

$("#string").on("keyup keypress paste mouseup", function () { 
    if (textTimer) clearTimeout(textTimer);
    textTimer = setTimeout(function(){
        var a = $('#string').val();
        $('#rdonly').html(a);
    }, 2000);

});
$('.btn').click(function() {
    $('#rdonly').text('');
    $('#string').val('');
});

Answer 7

You just need to modify your code as follows:

var timeoutId = 0;
$("#string").on("keyup keypress paste mouseup", function () { 
    var a = $('#string').val();
    // Cancel existing timeout, if applicable
    if (timeoutId > 0) {
        window.clearTimeout(timeoutId);
    }
    // Start a timeout for 2 seconds- this will be cancelled above
    // if user continues typing
    timeoutId = window.setTimeout(function () {
        $('#rdonly').html(a);
    }, 2000);
});