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My change event listener not tracking changes as expected [duplicate]

When using jquery .change on an input the event will only be fired when the input loses focus
In my case, I need to make a call to the service (check if value is valid) as soon as the input value is changed. How could I accomplish this?

UPDATED for clarification and example
examples: http://jsfiddle.net/pxfunc/5kpeJ/
Method 1. input event
In modern browsers use the input event. This event will fire when the user is typing into a text field, pasting, undoing, basically anytime the value changed from one value to another.
In jQuery do that like this
$('#someInput').bind('input', function() {
$(this).val() // get the current value of the input field.
});
starting with jQuery 1.7, replace bind with on:
$('#someInput').on('input', function() {
$(this).val() // get the current value of the input field.
});
Method 2. keyup event
For older browsers use the keyup event (this will fire once a key on the keyboard has been released, this event can give a sort of false positive because when "w" is released the input value is changed and the keyup event fires, but also when the "shift" key is released the keyup event fires but no change has been made to the input.). Also this method doesn't fire if the user right-clicks and pastes from the context menu:
$('#someInput').keyup(function() {
$(this).val() // get the current value of the input field.
});
Method 3. Timer (setInterval or setTimeout)
To get around the limitations of keyup you can set a timer to periodically check the value of the input to determine a change in value. You can use setInterval or setTimeout to do this timer check. See the marked answer on this SO question: jQuery textbox change event or see the fiddle for a working example using focus and blur events to start and stop the timer for a specific input field

If you've got HTML5:
oninput (fires only when a change actually happens, but does so immediately)
Otherwise you need to check for all these events which might indicate a change to the input element's value:
onchange
onkeyup (not keydown or keypress as the input's value won't have the new keystroke in it yet)
onpaste (when supported)
and maybe:
onmouseup (I'm not sure about this one)

With HTML5 and without using jQuery, you can using the input event:
var input = document.querySelector('input');
input.addEventListener('input', function()
{
console.log('input changed to: ', input.value);
});
This will fire each time the input's text changes.
Supported in IE9+ and other browsers.
Try it live in a jsFiddle here.

As others already suggested, the solution in your case is to sniff multiple events.
Plugins doing this job often listen for the following events:
$input.on('change keydown keypress keyup mousedown click mouseup', handler);
If you think it may fit, you can add focus, blur and other events too.
I suggest not to exceed in the events to listen, as it loads in the browser memory further procedures to execute according to the user's behaviour.
Attention: note that changing the value of an input element with JavaScript (e.g. through the jQuery .val() method) won't fire any of the events above.
(Reference: https://api.jquery.com/change/).

// .blur is triggered when element loses focus
$('#target').blur(function() {
alert($(this).val());
});
// To trigger manually use:
$('#target').blur();

If you want the event to be fired whenever something is changed within the element then you could use the keyup event.

There are jQuery events like keyup and keypress which you can use with input HTML Elements.
You could additionally use the blur() event.

This covers every change to an input using jQuery 1.7 and above:
$(".inputElement").on("input", null, null, callbackFunction);

Why browser doesn't fire change event

I have
<input type="text" id="pies" value="" />
and
$( document ).ready(function() {
$('#pies').on('change', function() { alert('cham'); });
$('#pies').focus();
$('#pies').val('kooooo');
$('#pies').blur();
});
Why browser doesn't fire change event? How can I make that browser will fire change event. I don't want to trigger "change" manually, because if I will trigger change, in some cases trigger change will be triggered twice. This is only example.

Call the change using :
$('#pies').change();

You have to do it manually
$('#pies').change();
As docs says
The change event is sent to an element when its value changes. This event is limited to elements, boxes and elements. For select boxes, checkboxes, and radio buttons, the event is fired immediately when the user makes a selection with the mouse, but for the other element types the event is deferred until the element loses focus.
In auto complete case try to do $("#pies").trigger("autocompleteselect");

Better use keypress instead of change

Detect date selection on an HTML5 calendar element, but not manually entered date

I need to be able to run a JavaScript function when a user clicks on a date in an HTML5 calendar element. I tried using onchange, but it also fires when the user types in a date:
<input type="date" onchange="alert('fired');"/>
It seems the event doesn't fire until they type in a "complete" date, which is neat, but doesn't meet my needs.
Is there a way to only fire when the date was clicked on in the calendar? Or maybe fire in both scenarios but detect which type of action it was?

I gather you want to disable keyboard input so user can only select valid dates by mouse.
You also want to detect clicks inside the calendar.
For that I have this updated demo of the answer:
Note how the click handler will have an empty string value for clicks on invalid dates.
InputDatePreventKeyboard
Please note that writing event handlers in HTML attributes is not recommended.
See
https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/eval#Use_functions_instead_of_evaluating_snippets_of_code
Here is the updated code of the demo:
<input type="date"
onchange="alert(window.event.type+' event handler for '+this.type+' noticed \''+this.value+'\'');"
onclick="alert(window.event.type+ ' event handler for '+this.type+ ' noticed \''+this.value+'\'');"
onkeydown="window.event.preventDefault();
alert(window.event.type+' event handler for '+this.type+' prevents keyboard input for value \''+this.value+'\'');"
onkeypress="window.event.preventDefault();
alert(window.event.type+' event handler for '+this.type+' prevents keyboard input for value \''+this.value+'\'');"
oninput="alert(window.event.type+' event handler for '+this.type+' noticed \''+this.value+'\'');" />

Determining whether focus was received as result of a click event

I have an <input> element that can either have the focus set via code, or as the result of a mouse click.
If the user clicks on the input, then the click event handler will fire - all well and good. If the element receives the focus via some other way (e.g. via code) then I want to manually trigger the click event so that the handler will also fire.
I could do this:
$elem = $('input');
$elem
.on('focus', function() { $(this).trigger('click') })
.on('click', function() { alert('Clicked!') });
However, this will result in click handler being fired twice; once for the click event and once for the focus event.
Is there any way to selectively trigger the click handler only if the focus was not received as the result of a click event?
UPDATE
This is a very simplified version of my problem, so I can't do things like bind both handlers to the focus event etc. I'm trying to merge two third-party pieces of code.

The .trigger() function adds a property isTrigger in the event object to identify that the event was triggered by its usage. Although, it is not documented the property is still present in jQuery 1.8.3 but it seems to only be used internally.
Anyways, you can make use of the extraParameters parameter to add a custom property to the event object. For instance,
$(this).trigger('click', {
isTrigger: true
});
It will keep the compatibility with isTrigger even if it is gone in a future release.

After doing some more research it appears that there is no way of guaranteeing which event will fire first: click or focus. (There doesn't seem to be a standard that dictates the order of events.)
This means that when the focus event fires there's no way to determine if a click event will or will not be triggered by the browser shortly afterwards.
I managed to solve the issue by using setTimeout() to run a test about 100ms after the focus event fired to check if the click event had fired. The third-party code that I was using (bound to the click event) added an extra class to the <input>, so I was able to check for that.

You can tap into the mousedown event which fires before the focus event. When you click a focusable object the order of events is as follows... mousedown, focus, mouseup, click.
You could set a flag in the mousedown event and then check for it in the focus event to see if the focus came from a mouse click. Obviously make sure to clear the flag in the focus event handler. Every application is different, but tapping into the mousedown event allows you to figure out a solution.
Here is a JSFiddle demonstrating the order of events... http://jsfiddle.net/ek7v7/

$elem = $('input');
$elem
.on('focus', function() { alert("Focused!") })
Focus can be fired by focusing the input by using tab, clicking it, or by using .focus()
Is there a reason for on('click', ...)?

OnChange event does not work properly

My OnChange event does not work properly - I want to trigger a function when user changes a textbox's value. But in my tests I have seen that the function triggers when textbox's value changes and textbox loses focus. Something wrong with my browser? Or is it about the ability of JavaScript? If the last one is true how can I can do that? Thanks in advance.

onchange event will trigger when an input field loses focus or when an option is selected from a dropdown menu, that's normal behavior.
If you want an event that will be triggered as the user types in an input field, you can use onkeypress, onkeydown or onkeyup events.

You could do with jquery:
$("textbox_id").keyup(function(){
//do something here
});

write the jquery code on keyup event and blur event also, because if user paste some copied data into textbox by using mouse only in that case only blur event called by jquery.