JavaScript onTap functions - javascript

Still new to the forums, so I'll try my best to get across the problem. Basically I'm developing a mobile web app, and have several ontap functions for reloading the webpage after buttons clicked. Here is the code for two of my smaller onTap functions for demonstration purposes (so you don't have to sift through hundreds of lines of code). The licenses_button ontap function works perfectly fine, with no forms of errors whatsoever, but the back_button ontap function, and all other buttons that aren't created on the initial main page of the app won't act as button's and I have no idea why. Any advice? (I know the back_button has little to no content, I just removed a lot of it for debugging purposes and even this fails to work). Thanks for any advice!
$("#licenses_button").onTap(function(event){
$("#play_button").remove();
$("#banner").remove();
$("#licenses_button").remove();
$(".cloud").remove();
$(".cloudalternate").remove();
$("body").append("<div id='back_button'>Back</div");
});
$('#back_button').onTap(function(event) {
$('#back_button').remove();
});

$(selector).onTap(callback); attaches the handler to the selected elements at the moment it is called. Elements that are not yet created at this time cannot be selected (obviously since they do not exist yet) and thus, won't get the handler.
You need to attach the handler after you added an element.
For example:
$("#licenses_button").onTap(function(event){
$("#play_button").remove();
$("#banner").remove();
$("#licenses_button").remove();
$(".cloud").remove();
$(".cloudalternate").remove();
// Create the button.
var backButton = $("<div id='back_button'>Back</div");
// Append it to the body.
$("body").append(backButton);
// Attach the handler to the new button.
backButton.onTap(function(event) {
backButton.remove();
});
});

You mentioned the back_button and other buttons that aren't working are not created in the main page. Since these are created at a later time, you have to wait to set up the onTap event for those buttons AFTER you create the buttons. If you try to set the event handler up before they're created, they won't work.

Related

Why only single change event is working on select element in jQuery?

I need to change behavior of jQuery library (date range picker), it have code like this:
box.find('.month').off("change").change(function(evt) {
dateChanged($(this));
});
box.find('.year').off("change").change(function(evt) {
dateChanged($(this));
});
Those are two select elements. It don't return false and functions inside handler don't access the event. But for some reason my events that use delegation doesn't work. They are ignored.
$picker.on('change', 'select', function() {
console.log('CHANGE');
});
The console log is not executing, but if I remove previous lines from the library, my event delegation code works fine.
NOTE: $picker is object in my code that is parent of box element. But I also have event added on $(document) that is also not working.
First time I see something like this. Adding event directly to element, prevents event propagation. Can someone explain what is happening here? Is this documented anywhere?
This happens in Firefox and Chrome.
If someone need simple example, I can create one. But thought that this is self explanatory.
EDIT: I've created a simple reproduction and it works fine. I have complex application with a lot of files (R Shiny Application), but I don't see any change events in dev tools. Are there any way of making the event not propagate? Maybe using event capturing. What should I search for in order to find the code that is preventing the events from propagating?

Wrote alternative to jQuery Accordion, it spazzed. Why?

I wrote an alternative to the jQuery Accordion, as that didn't offer multiple open section support (any idea why they opted to not include support for that? What's the history there?). I did some research on StackOverflow, as well on Google to see what other options others came up. I needed something that could be used on the fly on multiple elements.
After seeing several solutions and experimenting with them, in the end, I wrote my own version (based on Kevin's solution from http://forum.jquery.com/topic/accordion-multiple-sections-open-at-once , but heavily modified).
jsFiddle can be found here: http://jsfiddle.net/3jacu/1/
Inline Code:
$(document).ready(function(){
$.fn.togglepanels = function(){
return this.each(function(){
h4handler = $(this).find("h4");
$(h4handler).prepend('<div class="accordionarrow">▼</div>');
$(h4handler).click(function() {
$(h4handler).toggle(
function() {
barclicked = $(this);
$(barclicked).find(".accordionarrow").html('►');
$(barclicked).next().slideUp('slow');
window.console && console.log('Closed.');
return false;
},
function() {
barclicked = $(this);
$(barclicked).find(".accordionarrow").html('▼');
$(barclicked).next().slideDown('slow');
window.console && console.log('Open.');
return false;
}
);
});
});
};
$("#grouplist").togglepanels(); }
Oddly, the accordion arrow at the right side stopped working once I pasted it in jsFiddle, while it works in my local copy.
In any case, the issue is that toggling isn't working as expected, and when it does, it fires duplicate toggle events which result in it closing, opening, then ultimately closing the section and it won't open from that point on (it toggles open then closes back). That's assuming it works! At first, it won't work as it doesn't respond. I think there's a logic error somewhere I'm missing.
From what I wrote/see in the code, it searches the given handle for the corresponding tag (in this case, h4), pops the handle into a variable. It then adds the arrow to the h4 tag while applying the accordionarrow class (which floats it to the right). It then adds a click event to it, which will toggle (using jQuery's toggle function) between two functions when h4 is clicked.
I suspect the problem here is that I may be mistakenly assuming jQuery's toggle function will work fine for toggling between two functions, that I'll have to implement my own toggle code. Correct me if I'm wrong though!
I'm trying to write the code so it'll be as efficient as possible, so feedback on that also would be appreciated.
Thanks in advance for your time, assistance, and consideration!
You have the toggle binding (which is deprecated by the way) inside of the click binding, so a new event handler is getting attached every time you click the header.
As a random aside you should also fire events within the plugin (where you have the console lines would make sense) so that external code can react to state changes.
I believe your issue is the $(h4handler).click(function() { you have wrapped around the toggle listener. Essentially what this was doing was making so every click of the tab was adding the toggle listener, which was then also firing an event. Removing the click listener will have the behaviour you expect.
You forgot to paste the trailing characters ); to close the function call to jQuery function ready. Fixed: http://jsfiddle.net/LeZuse/3jacu/2/
UPDATE: I've just realised I did not really answer your question.
You are duplicating the .toggle functionality with binding another .click handler.
The doc about .toggle says:
Description: Bind two or more handlers to the matched elements, to be executed on alternate clicks.
Which means the click event is already built in.
NOTE: You should use local variables instead of global, so your plugin won't pollute the window object. Use the var keyword for this:
var h4handler = $(this).find("h4");

Sharing an event across two scripts or using change is visibility state as an event trigger

OK I am lost here. I have read numerous postings here and else where on the topic of how to check for the state of a given element in particular whether it is visible or hidden and make the change of state trigger an event. But I cannot make any of the suggested solutions work.
Firstly, as every one seems to leap on this point first, the need to do this has arisen as I have one jQuery script which deals with displaying an svg icon in a clickable state. And another which already has functions to perform relevant actions when the form is made visible by clicking the icon and obviously I want to reuse these.
What I have tried:
Initially I tried have both the scripts acting on a single click event (this remains the ideal solution)....
Script 1:
$(".booked").on("click", function() {
$("#cancellation_Form_Wrapper").css("visibility","visible");
}).svg({loadURL: '../_public/_icons/booked.svg'});
Script 2:
$(".booked").on("click", function() {
// do stuff
});
This did not work so I tried to research sharing an event across two scripts but couldn't make any head way on this subject so I tried triggering another event for the second script to pick up....
Script 1:
$(".booked").on("click", function() {
$("#cancellation_Form_Wrapper").css("visibility","visible");
$("#cancellation_Form_Wrapper").trigger("change");
}).svg({loadURL: '../_public/_icons/booked.svg'});
Script 2
$("#cancellation_Form_Wrapper").on("change", function(event){
// do stuff
});
This did not work again I am unclear why this didn't have the desired effect.
Then I tried is(:visible) ....
Script 1
$(".booked").on("click", function() {
$("#cancellation_Form_Wrapper").css("visibility","visible");
}).svg({loadURL: '../_public/_icons/booked.svg'});
Script 2
$("#cancellation_Form_Wrapper").is(":visible", function(){
// do stuff
});
So I am a bit lost. The ideal would be to return to the first notion. I do not understand why the click event on the svg cannot be handled by both scripts. I assume that this has something to do with event handlers but I am not sure how I could modify the script so they both picked up the same event.
Failing that I could use the fact the visibility state changes to trigger the action.
Any guidance welcomed.
Edit Ok I have just resolved the issue with script 2 picking up the triggered event from script 1. Sad to say this was a basic error on my part ... the form was preventing the display of the alert. However I still cannot get the is(:visible) to work.
Your syntax may be off:
$("#cancellation_Form_Wrapper").is(":visible", function(){
// do stuff
});
should be:
if($("#cancellation_Form_Wrapper").is(":visible")){
// do stuff
});
EDIT: If you want something to happen after a div is made visible, you may want to use the show() callback rather than toggling visibility:
$('#cancellation_Form_Wrapper').show(timeInMilliseconds, function(){
// do something
});
However, this needs to take place in the same function, which I don't think improves your position.
The problem is probably that your second on() script is firing at the same time as your first, meaning the wrapper is not yet visible. You could try wrapping the second on() in a short timeout:
$(".booked").on("click", function() {
setTimeout(function(){
if($("#cancellation_Form_Wrapper").is(":visible")){
// do stuff
});
}, 100);
});
That should introduce enough of a delay to make sure the wrapper has been shown before trying to execute the second statement.

JQuery if statement for .is(':visible') not working

I have a div that when the page is loaded is set to display:none;. I can open it up using this simple code:
$(".field-group-format-toggler").click(function()
{
$(".field-group-format-wrapper").css({'display':'block'});
});
Once it's opened, I'd like the user to be able to close it so I tried using the .is(':visible') function and then wrapping my original code in an if statment but this time using display:none;
if($('.field-group-format-wrapper').is(':visible')){
$(".field-group-format-toggler").click(function()
{
$(".field-group-format-wrapper").css({'display':'none'});
});
}
This does not seem to work though and I am not getting any syntax errors that I know of.
I also tried this:
if ($('.field-group-format-wrapper').is(':visible'))
$(".field-group-format-toggler").click(function () {
$(".field-group-format-wrapper").css({'display':'none'});
});
... but that did not work either.
You can just use the toggle function:
$(".field-group-format-toggler").click(function()
{
$(".field-group-format-wrapper").toggle();
});
This will show the '.field-group-format-wrapper' elements if they are currently hidden and hide them if they're currently visible.
FYI the reason your code snippet in your question wasn't working is because you're only checking the visibility of the elements on dom ready, rather than on each click - so the event handler to show the elements will never be attached.
I guess your function is only being called on page load at which time all divs are hidden.
Why not check the visibility in the click event handler?
$('.field-group-format-toggler').click(function(){
var $wrapper = $('.field-group-format-wrapper'); //Maybe $(this).parent()?
if($wrapper.is(':visible'))
$wrapper.hide();
else
$wrapper.show();
As already mentioned, you can use the toggle function to achieve what you want.
To add a bit of extra information, when attaching events like you're doing, you're actually using a subscription model.
Registering an event puts it in a queue of events subscribed to that handler. In this case, when you add the second event to change the CSS, you're adding an event, not overwriting the first one.
Whilst thing isn't actually causing your problem, it's worth being aware of.

Locating an element in a 'Facebox' box

Heres my link:
http://tinyurl.com/6j727e
If you click on the link in test.php, it opens in a modal box which is using the jquery 'facebox' script.
I'm trying to act upon a click event in this box, and if you view source of test.php you'll see where I'm trying to loacte the link within the modal box.
$('#facebox .hero-link').click(alert('click!'));
However, it doesn't detect a click and oddly enough the click event runs when the page loads.
The close button DOES however have a click event built in that closes the box, and I suspect my home-grown click event is being prevented somehow, but I can't figure it out.
Can anyone help? Typically its the very last part of a project and its holding me up, as is always the way ;)
First, the reason you're getting the alert on document load is because the #click method takes a function as an argument. Instead, you passed it the return value of alert, which immediately shows the alert dialog and returns null.
The reason the event binding isn't working is because at the time of document load, #facebox .hero-link does not yet exist. I think you have two options that will help you fix this.
Option 1) Bind the click event only after the facebox is revealed. Something like:
$(document).bind('reveal.facebox', function() {
$('#facebox .hero-link').click(function() { alert('click!'); });
});
Option 2) Look into using the jQuery Live Query Plugin
Live Query utilizes the power of jQuery selectors by binding events or firing callbacks for matched elements auto-magically, even after the page has been loaded and the DOM updated.
jQuery Live Query will automatically bind the click event when it recognizes that Facebox modified the DOM. You should then only need to write this:
$('#facebox .hero-link').click(function() { alert('click!'); });
Alternatively use event delegation
This basically hooks events to containers rather than every element and queries the event.target in the container event.
It has multiple benefits in that you reduce the code noise (no need to rebind) it also is easier on browser memory (less events bound in the dom)
Quick example here
jQuery plugin for easy event delegation
P.S event delegation is pencilled to be in the next release (1.3) coming very soon.

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