Javascript for when AjaxControlToolkit TabContainer is ready? - javascript

I have a page with a TabContainer control (from the Ajax Control Toolkit), and I toggle the visibility of some elements on the page depending on the currently-selected tab. I'd been doing this in an event handler for OnClientActiveTabChanged (which works fine), but I discovered that it leaves the page in the wrong state after a postback. I tried adding some code to the document.ready event handler to get the index, but when I do the following:
$(document).ready(function () {
var index = $('#<%= TabContainer1.ClientID %>').[0].control.get_activeTabIndex();
// Do some stuff with the index
});
...I get a null reference exception on the .control property. Is there a way to hook a client-side "ready" event for the TabContainer?
I’m not familiar with the event lifecycle with normal DOM elements (it seems like there ought to be a general onload event, but I don’t see one). If there isn’t an event that can be easily handled, it seemed like it might work to add an UpdatePanel with UpdateMode=Conditional and an AsyncPostBackTrigger that pointed to a hidden button with an onclick event handler that would get the active tab index – but that seems like a lot of moving pieces for something that I’d expect the DOM to expose already.

Too late to be helpful, but I've had the same issue and found a workaround.
Change you code
$(document).ready(function () {
var index = $('#<%= TabContainer1.ClientID %>').[0].control.get_activeTabIndex();
// Do some stuff with the index
});
to
function pageLoad() {
var index = $('#<%= TabContainer1.ClientID %>').[0].control.get_activeTabIndex();
// Do some stuff with the index
};
Explanation here:
http://encosia.com/document-ready-and-pageload-are-not-the-same/
Basically, jQuery's ready event is "a bit early" and the TabContainer is not initialized yet, whereas the client side ASP.Net's pageLoad is late enough and the TabContainer has been initialized by then.

Check this post to save tab selection during postbacks. It works for normal post backs by saving the active tab index in hidden variable. Though its written for a JQuery plugin in the posted link, concept should be the same i.e., persisting the index of the selected tab.

Related

onChange event firing incorrectly after being loaded programmatically

I have an APEX application where there are many drop down items. I've bound change event handlers to them using the bind function of jQuery.
Now when I load the content of a drop-down programmatically using $('#ELEMENT').trigger('apexrefresh'), the drop-down reloads but the change event handler fires automatically.
How do I prevent this from happening? I tried avoiding binding the event handler using bind and instead adding the onChange attribute to the element. The incorrect behaviour was still present.
Here is the skeletal code:
$(document).ready(function()
{
$('#P7021_MSG_DEF').bind('change', function(e)
{
console.log('bound function onChange() msg_def');
updateStartWord();
}
);
});
function updateMsgDef()
{
console.log('function updateMsgDef() ');
$('#P7021_MSG_DEF').one('apexafterrefresh', function()
{
if( $x('P7021_RESTORE_CHK').value == 'Y')
{
setdefault('P7021_MSG_DEF', vJson.msg_def);
}
updateStartWord();
}
).trigger('apexrefresh');
}
In the above code, when the updateMsgDef is called from another function the function updateStartWord() gets called twice - once by updateMsgDef() itself and again by the onChange handler that was bound to P7021_MSG_DEF item.
If anyone could help on this?
Calling $('#ELEMENT').trigger('apexrefresh') is going to trigger the change event. Short of going back to the drawing board altogether, the solution is going to be a hack whatever you do. You could poke about in (and quite possibly break) Oracle's javascript. You could write your own AJAX to populate the select list.
The easiest way might be to check in your onChange event which element currently has focus, eg:
onChange = "if($( document.activeElement).attr('id')=='YOUR_PAGE_ELEMENT')
{ $( document.activeElement).trigger('apexrefresh'); };"
If the user has changed the select list, it should still have focus. There's no guarantee that will work in all browsers, but I think it should be ok in current Chrome and IE versions.
I've been in a similar situation to yours, and have come to accept that if the page logic is too complicated to implement using DAs, maintaining it is likely going to be a nightmare whatever happens. Much as I like "proper" programming, Apex is really all about the declarative controls.

How do I bind a click event to an object that is not yet in the DOM?

First of all, I tried the answers in this, and this similar questions, but that does not seem to work for me at all.
I would like to do stuff on a click event bound to an element that is created via ajax so it is not in the DOM at first.
I notice that the following coffeescript in my_asset.js.coffee works as expected:
$ ->
$('#div').on "click", ".link", (e) ->
#do stuff
According to JQuery Doc:
this function is bound to all "selected_div" click events, even if they are added to the DOM via ajax later
And the do stuff part works ok
However I would like to:
$(this).after("<%= insert some long view here %>")
So, in order to do that, I guess I should move the $(this).after part from the asset.js.coffee to my_view.js.erb
where I could embed render partial
There, in my_view.js.erb, I have tried the following, (equivalent) javascript:
$(function() {
$("#div").on("click", ".link", function() {
$(this).after("<%= render partial here %>");
});
});
But it does not work for the first click, (it does, however, for the subsequent clicks)
I think it is related to the fact that .link is not in the DOM when the page loads for the first time.
Why is this happening? Is that the cause? And how could I get in the view the same behaviour that I get in the asset ?
You'll bind to a container element (typically document or body), and delegate the event to the to-be-created object:
$(document).on("click", "#div .link", function() {
$(this).after("<%= insert some long view here %>");
});
Binding
As you've pointed out, JS binds events to elements of the DOM on page load
If your element is not present at load, JS won't be able to bind, thus causing a problem. To fix this, you'll have to delegate the bind to an element higher in the DOM hierarchy, allowing JS to bind the event to any new elements in relation to your container

How to bind to submit event in jQuery Mobile pages

Tried to bind submit event (or click or whatever) to an element within a jQuery mobile page. What I wanted to do is get the value from an input within an form element within a jQuery page and store it in cookies/localStorage. Every time I come back to this page I want to restore the input field.
Currently I ended up in using this script:
$('.pageClassSelector').live('pageinit', function (e) {
$('.classSelector').submit(function () {
var q = $('.inputClassSelector').val();
// store to localStorage ...
});
// load from localStorage ...
$('.q').val(lastSearchString);
});
This approach is documented there http://jquerymobile.com/test/docs/api/events.html
Since it seems possible that identical pages are hold in the DOM, ID selectors are not quite useful. My problem now is that everytime I navigate to this page the submit event is bound again and thus results in storing DIFFERENT (!) values. The submit event seems to be fired multiple times and much more interesting with the value before last.
Am I doing anything completly wrong? Any hints how to do scripting in jquery mobile properly?
TRY1:
I placed now the submit event binding within the pagebeforeshow event like so:
$('#PageId').on('pagebeforeshow', function (e) {
$('.classSelector').on('submit', function () {
var q = $('.q').val();
alert('stored: ' + q);
}
$('.q').val(lastSearchString);
}
But the value going to be stored is still the value before last, when I was navigating the page before. The first time it works as it should.
TRY2:
This is what I have now and it looks like it does that what I want. I select now the current page and select only the form which is a child of this page.
Is this good practice?
$('div:jqmData(id="PageId")').on('pagebeforeshow', function (e) {
$(this).find('#form').on('submit', function () {
var q = $(this).find('#input').val();
localStorage.setItem("key", q);
return true;
});
lastSearchString = localStorage.getItem("key");
$(this).find('#input').val(lastSearchString);
});
Your requirement to load from local storage and store on the page needs to be done by binding to the pagebeforeshow event (look at the section "Page transition events") and not the pageinit event like you are currently doing.
$('.pageClassSelector').on('pagebeforeshow', function (e) {
// load from localStorage ...
$('.q').val(lastSearchString);
});
Furthermore generally each page element (where you have data-role='page') should have a unique ID so you can use that instead of the CSS selector.
Multiple events firing when navigating pages sounds like multiple bindings to me, which is a known problem with jQuery Mobile. Bindings are not unbound when navigating pages, because everything is loaded through AJAX. See for example this StackOverflow Question: Jquery mobile .click firing multiple times on new page visit or my solution.
$('.classSelector').on('submit', function(){})
Try to use the constraction to bind your event to element.
Look likes some data was loaded through ajax request

jquery event added multiple times

I have a fairly large javascript class that generates an complete ajax-generated application. In one version of the ajax page there are a number of dropdown menus. These menus can get created and destroyed at various points during the life cycle of the application.
This is the behaviour I see:
User opens page version 1: no dropdowns
User goes to page version 2: dropdowns added with jQuery onchange event. Work as intended.
User returns to version 1 of page, dropdowns removed.
User returns to version 2 of page, dropdowns added again (using same element IDs)
dropdowns will now have 'double' event handling, triggering the event for each onchange.
The behaviour I'm struggling with is as follows.
On the initial page load, I add an onchange event:
function myClass(){
//Initiate once for current and future elements.
jQuery(document).on('change',".mydropdowns",
function(e){
self.submitDescriptionChange(this);
}
);
}
myClass.prototype.submitDescriptionChange = function (el){
doSomeAjaxStuff();
}
This works fine, except that each time the user goes to pages version 1 and returns to page version 2, the event gets multiplied. Very quickly you can end up with the event firing 20 times per change event, which in this case creates 20 ajax calls.
Logically, by using jQuery.off() I should be able to avoid this. But what happens instead is that the event is removed from both past and future elements, which means that when I recreate page version 2, the dropdowns won't work.
Every way I have tried this (and I've tried LOADS), I either end up with no event firing, or multiple events firing. I cannot seem to find a way to add/replace the elements whereby the event is only ever fired once.
Any ideas how I can solve this?
UPDATED
Yeah, so it turns out I misdiagnosed the problem. It actually came from repeatedly rebinding a 'hashchange' event, rather than rebinding the onchange event. Apologies for misdirection. Moving to bind() function to somewhere where it only executed once fixed the issue.
Since you do not want .off() to remove your events from other pages, I would suggest using namespaces for your events. For example, something like this:
function myClass(pageno) {
var pref_ev = 'mypage' + pageno + '.' + 'change';
$(document).off(pref_ev).on(pref_ev, ".mydropdowns", function(e) {
self.submitDescriptionChange(this);
});
}
This way, each page will have its own "change" event such as "mypage1.change". The event is still registered normally as a change event; the prefix namespace "mypage1" is used to only perform the .off() call on the right events.
I am not sure what plugin you are using for your dropdown menus but there should be a "destroy" method on that plugin. If you call that when removing the dropdowns that should work. Also, if you are only hiding the second page and not actually removing it from the DOM you dont have to re-invoke the plugin as the plugin will still be saved on the element.

how to prevent mutiple registration of a single event handler in jquery

I have a <div> box displaying search message and some radio button for recent message. There is link option for slide toggle.
When you click on that link it will show some input field and check box and radio button. And at the same time the text of link change to hide option. If you click on that it will hide all the input and checkbox option.
When I refreash the whole page its working properly but when that paticular box or part is refreashing then the box is hiding and imediately hides. If you refresh that portion n number of times the box is going on toggling continously. I think the problem is in registration of event handler. So please give me some solution.
CODE :
$(document).ready(function() {
$(".SideBar-blockheader1").click(function() {
e.preventDefault();
$(".SideBar-blockcontent1").slideToggle("fast");
});
$(".SideBar-optionheader").click(function() {
$(".SideBar-optioncontent").slideToggle("fast");
$(this).text($(this).text() == $("#hideopt").attr('value') ? $("#showopt").attr('value') : $("#hideopt").attr('value'));
});
$(".SideBar-optionheader").text($("#showopt").attr('value'));
$(".SideBar-optioncontent").hide();
});
jQuery has a method, called data() which can be used to extract the attached handler information of an HTML element. You can see if the element has already a click handler, and if it has, then stop re-attaching another handler to it.
if(typeof $('#id').data('events').click == 'object')
{
// A click handler is already attached
}
else
{
// No click handler; Attach one;
}
Although you haven't provided code, I suspect you are using .click(). For jQuery 1.7+ you should be using .on() in delegate mode (the element you bind to is an ancestor, not the clickable element itself) or .delegate() if pre jQ 1.7.
For example:
$('someAncestor').on('click', 'a.specialLink', function(event) {
event.preventDefault();
// the rest of your code for the click handler
})
"someAncestor" is any valid selector that is an ancestor of your link that will not be destroyed, rebuilt, or otherwise manipulated after the DOM is built. It doesn't have to be the direct ancestor.
[updated below after seeing code sample and comments]
There are a few things going on. First, .on() will only work if you're using jQuery 1.7+. Next, .on() can be invoked a few different ways (I wrote about it here: http://gregpettit.ca/2011/jquery-events-its-on/) and you need to be invoking it while delegating an ancestor listener, not simply as a substitute for click. Next, you haven't provided code for your attempted update, only for the original code; it's hard to tell what "didn't work" about trying to use .on(). Moving along, I'm not actually sure what this line is meant to do:
$(this).text($(this).text() == $("#hideopt")...etc...
I can't think of why you would want to try to treat a jQuery object as a variable. I'm not saying the code is wrong, I'm just saying I don't get it. Also, I hate ternary operators... which is part of the reason I don't get it. I much prefer readable conditionals. ;-)
Next, you're calling preventDefault() on "e" but you're not passing "e" into your functions. You might just be getting a JavaScript error, period. (e is undefined)
Then there's attr("value") which I believe should actually work. But why not use .val() if it is indeed a node that HAS a value attribute?
Finally, there is tonnes of room for caching your objects. Every time you see that an object is being used more than once, you can benefit (to varying degrees of performance and legibility) from caching it. I have not updated the code with any caching, though-- that's really something for a whole other "How can I best cache my objects?" question.
Anyhow... to solve the problem, you first have to choose a valid ancestor. This can be any ancestor that isn't destroyed during the process of loading in your new data. This could be anything, but the closest ancestor is the best. It might be a section wrapper, but if you're truly desperate it could be a page wrapper or even the body tag. If you bind to document, you're reproducing the deprecated .live() function, which I definitely recommend against. I have used a placeholder selector, ".section" but you need to figure out what an appropriate ancestor is on your page.
$(document).ready(function()
{
$(".section").on("click", ".SideBar-blockheader1", function(e)
{
e.preventDefault(); // probably not necessary if there's no default click behaviour
$(".SideBar-blockcontent1").slideToggle("fast");
});
$(".section").on("click", ".SideBar-optionheader", function(e)
{
e.preventDefault(); // probably not necessary if there's no default click behaviour
$(".SideBar-optioncontent").slideToggle("fast");
$(this).text($(this).text() == $("#hideopt").val() ?$("#showopt").val() : $("#hideopt").val());
});
$(".SideBar-optionheader").text($("#showopt").val());
$(".SideBar-optioncontent").hide();
});

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