javascript event - javascript

I have an interesting question, i hope..I have a textarea in my form..when a user comes to enter values in it it displays some cached values in an autocomplete format..thats fine..I want to call an ajax function after the user selects such a cached value in it..so that the ajax call should pass this selected value..so my question is on which can i get the final selected value, so i call ajax at that time,... i tried with onblur etc, but not worked..
help please..
thanks in advance...

If the user chooses by clicking, you want a 'click' handler on the element the user is selecting (or a containing element).
If the user can select in other ways, eg by the keyboard, then you'll need to observe other events as well.

You mean you want to detect if the user selects a value the browser's native Autocomplete lookup, instead of typing it in themselves?
I'm certain there is no event to catch this.
The only workaround that comes to mind is analyzing the keypress events the user makes in the input field. If the keys entered do not match the full string that is in the text field, and no onpaste event was fired, it stands to reason that the value was selected from an Autocomplete.
This is going to be tough to implement, though, and by no means 100% reliable.

As Pekka said above, there will likely be browser-specific events to handle for this kind of functionality, but it is possible.
For IE, check out Why does the javascript onchange event not fire if autocomplete is on? for a reference to the "onpropertychange" event within IE.
For Firefox, it looks like others have solved it through a combination of onBlur and onFocus (see FireFox capture autocomplete input change event).
If you do come up with a cross-browser solution, please let us know!

Related

Detecting a change in radio button/checkbox state

I need to reliably detect the state change of radio buttons/checkboxes on my page in order to watch if the form was modified or not. Now, this is a completely separate script, I cannot modify anything that controls the form.
Right now, I can see only two ways of doing this:
onchange event handler, which helps with textboxes, textareas and selects, but is not fired for checkboxes/radiobuttons
onclick event handler, which is not reliable, because users often use hotkeys to change the values of these elements.
What am I missing here? Is there a way to reliably detect that checkbox was checked/unchecked?
UPDATE: As you guys pointed out, change event is really fired on checkboxes/radiobuttons, despite the fact that w3schools says it is only for text inputs
However, my problem turned out to be that the values of checkboxes/radiobuttons are set via setAttribute in scripts and in that case the event is not fired.
Is there anything I can do in this case?
See: http://www.quirksmode.org/dom/events/change.html.
It says that all major browsers support change event but the IE's implementation is buggy.
IE fires the event when the checkbox or radio is blurred, and not when it is activated. This is a serious bug that requires the user to take another action and prevents a consistent cross-browser interface based on the change event on checkboxes and radios.
I think you can overcome IE's bug with this trick. blur() elements when they focued! (Use something like $('input[type=radio]').focus(function(){$(this).blur();}); in jQuery or use pure javascript)
Ok, after some digging, here is what I found out. Note, this is applicable to Firefox, and, probably to Firefox only. Since in this case I was dealing with internal application, this was enough for me.
So, basically, in order to reliably detect changes in checkbox/radiobutton state in Firefox, you need to do two things:
Set up custom Firefox's event handlers CheckboxStateChange and RadioStateChange for checkbox and radiobutton respectively. These events will be fired when the user changes the inputs or when it is modified via script, using setAttribute, however, these events are not fired, when the state is changed in the script, using checked or selected properties of these elements, this is why we need ...
Watch the changes of the checked property using Object.watch
Standard onchange event is no good, since it only fired when user changes the value directly.
Damn, this thing is broken...
If people get interested, I'll post some code.

Catching all changes to the contents of an input box using JavaScript/jQuery

I have a page with an input box, and a function that processes the value of this input box and produces piece of text. I want this text to always be up to date in relation to the contents of the input box, so I've attached a couple of event handlers to it with jQuery to catch any changes:
$('#input').bind('keyup cut paste', function(){...});
This works well in most cases. Whenever the user modifies the contents using the keyboard in any way, or right-clicks to use the cut or paste functions, the text is updated immediately. However, there are two events I still haven't figured out how catch, if it's even possible to do so:
When the user selects a of text and drags it do a different position in the input box
When the user uses the Delete action in the right-click context menu
Both of these can of course be detected by binding the change event, but the problem with that approach is that it doesn't fire until the input box loses focus. The whole point of these bindings is to have the text update in real-time as the value of the input box changes, so change is no good.
English is my second language so I could simply be bad at wording my Google searches, but so far they've turned up nothing. I haven't found any solutions to this after digging through a couple of related Stack Overflow pages either, so I'm asking here. Is there an event binding for this that I don't know of? If not, is there a different approach I could take? Or is this simply not possible with plain JavaScript?
In non-IE browsers, you can handle the input event.
In IE, you can handle the propertychange event.
Demo (works in all browsers)
It's possible this SO question (and related jsfiddle) might answer your question.
(On the linked jsfiddle, put text in the top box to test)
In other words, bind to mouseup and mousedown, etc.
If you can't find a combination of events that cover all cases, you may want to use setInterval(function() {... }, period). You could play around with the period to see how well this works.

What events are fired when a user selects from the browsers stored form dropdown?

I'm using jQuery to alter things when a user enters text into an input. This works fine with .keydown() or .change() when typing.
I'm unable to capture an event when the user selects from the browser stored inputs for that field. This is the dropdown that appears when typing or on click when the element already has focus and the browser has previously entered items for this input.
Anyone know what event I can use to capture the population of the input by the browser from a stored list of previous inputs when the user clicks on one or uses the keyboard?
EDIT: As requested an example would be https://launchpad.37signals.com/highrise/signin (the Username and password, not openID). This hides the label for pasting, selecting from previous inputs or typing. I want to emulate this.
Thanks,
Denis
There's not one event triggered. As you said, it depends on how the user is using it : keyboard or mouse.
If I can remember well, keyboard approach triggers nothing. You should bind on the blur() event.
The mouseup should work for the mouse approach.
But whatever since you can bind several event at once thanks to
$("#id").bind("blur mouseup", function(){
alert("bound !");
});
The change event will fire as well, but when the element looses focus.. (like it normally does)
You would have the same issue even without the browser cache, if someone use the right-mouse-click -> paste of something they had in the clipboard ...
What about mouseup event? did you try it on the input?

How can a javascript function be fired when a user types text into an input field or pastes text into it?

$(document).ready(function() {
$("input[id^='question']").live('keyup',function(ev){
id=this.id.substr(8);
if (ajaxCallTimeoutID != null)
clearTimeout(ajaxCallTimeoutID);
ajaxCallTimeoutID = setTimeout(function(){subjectivecheck(id)}, 1000);
});
});
There is a problem. When a user pastes text into an input field, the function above can not be fired. How to solve this problem?
The onchange event is what you want here. It fires when the textbox loses focus (blur) and has had its value changed since it received focus. It takes care of the paste problem.
So instead of .live('keyup', use live('change'.
This is as good as it gets, without using some ridiculous interval polling. And just for the purpose of context, be aware that any user can disable Javascript in the browser whenever they feel like it.
The Paste (onpaste) event is not standard - it is AFAIK supported only in Internet Explorer (see: http://msdn.microsoft.com/en-us/library/ms536955(VS.85).aspx)
The change (onchange handlder) event is standard - but that will only fire if the value of the textbox changed in the time between gaining and losing focus - i.o.w. detecting change requires the textbox to lose focus.
What you could do, is use setInterval() (http://www.w3schools.com/jsref/met_win_setinterval.asp) to poll the value of the textbox, and compare it with the previous value.
At the onfocus event on the field, you can start a timer to check if the field value has changed.
And at onblur, clear that timer.
The paste with ctrl+v is ok with onkeyup, but not with the mouse right click or with a browser undo.
That's not the only problem. Even if you could catch cut and paste reliably on all browsers, which you can't, there are still more ways of putting content in a form field. For example on some platforms dragging a file to an input will put the pathname in, with no event for you to catch. Or a user might do right-click-Undo to change the contents. Or Delete. Or select some text from the input or another input and drag-and-drop it in. And probably many more I haven't thought of.
If you want to be informed of all changes to a form field more quickly than onchange, I'm afraid there is no alternative but to constantly monitor the value of the element in a polling setInterval.

Capturing HTML Text Input Key press after key has been applied?

A total newbie question, so please bear with me here ;)
When a key press occurs in a HTML text input control, there are two events that seem useful in managing it (onKeyPress and onChanged). onKeyPress fires after the key has been pressed, but before the operation has been applied to the control's text. The later is only fired when focus is removed from the control and edits were made.
My question: Is there a way to capture the event, after the key press has been applied to the control but w/o removing focus (so I can work off of the resultant text)? Or is this pretty much the options I have to work off of?
Thanks!
You may also want to look at onkeyup and onkeydown events. I suspect you're interested in onkeyup. Perhaps you could provide more info and I could give a more complete example.

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