jquery on does not react to element added by clone() - javascript

I was under the impression that jquery's on() reacted to events attached elements dynamically added to the dom (via ajax or cloning, etc). However, the following is only working for the element attached to the dom at page load. The other copy I make of it using clone() is not being, well, handled.
$(document).ready(function () {
$('.ship_via_dropdown').on('change', function () {
console.log($(this));
if ($(this).hasClass('prev_change')) {
console.log('has');
} else {
$(this).addClass('prev_change');
console.log('hasn\'t');
}
});
});
Code for cloning:
$(document).ready(function(){
var form1 = $('.line_item_wrapper').children().clone();
$('#new_line_content_1').html(form1);
});
HTML for dropdown (contents added by jquery db query on document ready)
<span class="select ship_via_select_container">
<select class="ship_via_dropdown ship_via_dropdown_1">
</select>
</span>
Thank you for any insight!

Either delegate the event instead:
$(document).on('change', '.ship_via_dropdown', function () {
console.log($(this));
if ($(this).hasClass('prev_change')) {
console.log('has');
} else {
$(this).addClass('prev_change');
console.log('hasn\'t');
}
});
Or better yet, use .clone(true) to clone with events. (Note: this will only work if you're cloning AFTER the event handler is attached.)

It does, but not in the way that you think. When used as you have used it:
$('.ship_via_dropdown').on('change',
It is really not different than using .change(). What you are looking for is event delegation. This takes the following form:
$("<selector to static ancestor>").on('change', '.ship_via_dropdown', function () {
Where <selector to static ancestor> is a selector to a static ancestor of the dynamically added elements. (one that is not dynamically created) As a last resort document can be used here. However for performance, this should be the closest static ancestor element.

jquery's on() reacted to events attached elements dynamically added
No - or at least, only if you use it with delegated events. The live method did always delegate events to the document.

Change this line:
$('.ship_via_dropdown').on('change', function () {
to this:
$(document).on('change',".ship_via_dropdown", function () {

Related

How to select parent using on selector

I have a dynamic hover that gets activated based on whether a hidden element exists or not. I'm updating my code to incorporate dynamically created elements but have ran into an issue and don't know how to select a parent.
Previously I used $(".infotip").parent().hover but have updated to:
$(document).on("mouseenter", ".parent-selector", function() {
$(this).find(".infotip").addClass("active");
});
$(document).on("mouseleave", ".parent-selector", function() {
$(this).find(".infotip").removeClass("active");
});
So what needs to happen is I need ".parent-selector" to behave like $(".infotip").parent()
Since the content is dynamic and you mentioned you can't add a class to the parent when it's created, the only way I can think to do this would be to watch for any new elements that have been added and then bind your events.
This function will periodically look for any elements with the .infotip class that does not have our custom events_bound attribute already. If it finds one, it'll add the attribute and then bind the mouse events to the parent. I've included a fiddle illustrating this with dynamic content.
//check for changes in the dom
setInterval(function() {
$('.infotip:not([events_bound])').each(function() {
//add attribute so that we don't re-bind to this element
$(this).attr('events_bound', true);
//now bind the events to the parent
$(this).parent().mouseenter(function() {
$(this).find(".infotip").addClass("active");
})
$(this).parent().mouseleave(function() {
$(this).find(".infotip").removeClass("active");
})
});
}, 500);
https://jsfiddle.net/ybrwv0c8/1/
Of course if there is anything identifiable about the parent, then the best way would be to use a selector for your on. For instance, if there's a dynamically generated ID with a standard structure like parent_13835723, you could do a partial attribute selector like $('[id^=parent_]')
You might also be able to use use the jquery :has pseudoselector like so. However, this searches all descendants for an element, which may not work correctly depending on how your DOM is structured.
$(document).on("mouseenter", ":has('.infotip')", function() {
$(this).children('.infotip').addClass("active");
});
$(document).on("mouseleave", ":has('.infotip')", function() {
$(this).children('.infotip').removeClass("active");
});
However, according to the jquery docs here http://api.jquery.com/has-selector/:
The expression $( "div:has(p)" ) matches a <div> if a <p> exists anywhere
among its descendants, not just as a direct child.
Because :has() is a jQuery extension and not part of the CSS
specification, queries using :has() cannot take advantage of the
performance boost provided by the native DOM querySelectorAll()
method. For better performance in modern browsers, use $(
"your-pure-css-selector" ).has( selector/DOMElement ) instead.
I'm not sure whether the :has or setInterval method would have better performance.
How about
$(".infotip").parent().mouseleave(function() {
$(this).find(".infotip").addClass("active");
}
and
$(".infotip").parent().mouseleave(function() {
$(this).find(".infotip").addClass("active");
}
Reference : https://api.jquery.com/mouseleave/
You can use jQuery's custom :has selector:
$('document').on('mouseenter', ':has(.infotip)', function () {
$(this).find(".infotip").addClass("active");
});
$('document').on('mouseleave', ':has(.infotip)', function () {
$(this).find(".infotip").addClass("active");
});
I haven't tested this, as there is no HTML provided in the question, but the documentation seems to indicate it will do what you want.
As simple as
jQuery(".child").parent().on('mouseenter', function(){
jQuery(this).css('background', '#f00');
});
jQuery(".child").parent().on('mouseleave', function(){
jQuery(this).css('background', '#0ff');
});
DEMO
Edit:- Based on further clarification,
You can attach events to objects when you create them. If you are binding the same events to multiple objects at different times, just create a named function.
OR
A really dirty hack would be to to unbind and rebind the events everytime a hirerchy of elements is added to the DOM.
Something like
var init = function() {
jQuery(".child").parent().off().on('mouseenter', function(){
jQuery(this).css('background', '#f00');
});
jQuery(".child").parent().off().on('mouseleave', function(){
jQuery(this).css('background', '#0ff');
});
};
Just call the method init everytime you add something to the DOM.

Check if image was clicked JQuery

I want to know how to check if my image was clicked using jquery...
Here is my html code
<img class="img-fade" src="img/message.png" id="messages" />
And my jquery code im using:
$('#messages').on("click", "img", function (e) { alert('hi'); }
But it still isnt working,
Could anyone help? Thanks :D
When you do:
$(selector1).on(event, selector2, function);
jQuery binds a handler to the event on the DOM elements that match selector1. When this handler runs, it walks the DOM hierarchy from the most specific element up to the element matching selector1, and checks whether any of the elements matches selector2. If it finds a match, it calls function with the appropriate execution context.
This is how on() is able to handle events on DOM elements that are added dynamically after the delegation is created.
i want to know how jquery' delegate or on(for delegate) works
In your case you made selector1 and selector2 the same element which caused trouble.
You can try this too
$('#messages').click(function(){
alert('hi');
}
$(function() {
$('#messages').on("click", function (e) {
$('.content2').fadeOut(3000);
window.setTimeout(function() {
window.location.href = 'messagecenter.html';
}, 3050);
});
});
I just fixed it :)
Instead of having $('#var').on("click", "img", function(e)) {});
I just removed the "img" part which I don't think was needed.
Thanks :)

jQuery won't bind click to underscore template using .on() for items added via function

I'm using underscore to create some elements and appending them to a div with jQuery.
At the bottom of the page I'm using jQuery's .on() to respond to clicks on the elements.
$('.pickup').on('click',
function(e) {
alert("hello");
}
);
Via some user interaction (in Google maps), I've got to add more elements to the div and want them to respond to clicks as well. For some reason they do not. I've pared it all down on jsfiddle:
http://jsfiddle.net/thunderrabbit/3GvPX/
When the page loads, note that clicking on the lines in output will alert('hello') via jQuery.
But click the [add] button and the new lines do not respond to clicks.
My HTML
<div id="unit_2225" class="pickup">
<span>Click me; I was here first</span>
</div>
<script type="text/template" id="unit-template">
<div class="unit-item">
<span class="pickup">
<span>click us (<%= unit_id %>) via underscore</span>
</span>
</div>
</script>
<div id="divID">
</div>
<button>add</button>
My Javascript
var addUnitToDiv = function(key,val) {
console.log(val);
var template = _.template($('#unit-template').html(),val);
$('#divID').append(template);
}
var unit_ids = [{unit_id:'hello'},
{unit_id:'click'},
{unit_id:'us'},
{unit_id:'too'},
{unit_id:112}];
$.each(unit_ids, addUnitToDiv);
var unit_pids = [{unit_id:'we'},
{unit_id:'wont'},
{unit_id:'respond'},
{unit_id:'to'},
{unit_id:'clicks'},
{unit_id:358}];
createMore = function() {
$.each(unit_pids, addUnitToDiv);
}
$('.pickup').on('click','span',function() {
alert("hello");
});
$('button').click(createMore);
I found a similarly worded question but couldn't figure out how to apply its answer here.
Instead of binding events directly to the elements, bind one event to their container element, and delegate it:
$("#divID").on("click", ".pickup", function () {
// Your event handler code
});
DEMO: http://jsfiddle.net/3GvPX/3/
In this case, the event handler is only executed for elements inside of the container #divID that have the class "pickup".
And in your scenario, the elements are being added to the element with an id of "divID". Thus, where the two selectors came from.
This is handy because, as you've found out, dynamically adding elements doesn't magically bind event handlers; event handlers bound normally with .on() are only executed (bound) on those present at the time of binding.
It could even help if you change the delegated selector to "span.pickup" (if you know the elements will always be a <span> like in your template), so that the DOM is filtered by the tag name first.
Reference:
http://api.jquery.com/on/#direct-and-delegated-events
Working demo http://jsfiddle.net/u2KjJ/
http://api.jquery.com/on/
The .on() method attaches event handlers to the currently selected set of elements in the jQuery object. You can attach the handler on the document level.
Hope it fits the need, :)
code try the code changed below
$(document).on('click','.pickup',function() {
alert("hello");
});

Dynamically added javascript is not working, but static code works fine?

Here is what I'm doing... I have a textbox that users type something in and click an add icon. This fires some jquery code that adds the item they typed into a span within a "content" div. The generated code has a delete icon that appears on hover and when clicked it should make the span disappear. This works if the code is on the page already (before document load) but if it's dynamically created, it breaks the delete on click functionality.
Here is a JSfiddle so you can see it in action: http://jsfiddle.net/WF32y/
What can I do to fix this? I essentially want to do what happens on here (stackoverflow.com) when you enter tags to a new question.
Use event delegation for dynamically added elements by changing this:
$('a.delete').on('click', function(e) {
Into this:
$(document).on('click', 'a.delete', function(e) {
Fiddle
.on() Direct and delegated events reference
Also, concerning performance, you can attach the handler to a closer ancestor of the dynamically added elements than the document (e.g. a static wrapper element).
You can easily do it with delegate. In your case:
$('#container').delegate('a.delete','click', function(e) {
e.preventDefault();
taskID = $(this).closest('.task')[0].id;
$(this).closest('.task').fadeTo(300, 0, function() {
$(this).animate({
width: 0
}, 200, function() {
$(this).remove();
});
});
});
And by the way FYI:
// jQuery version 1.4.3+
$('#container').delegate('a.delete'...
// jQuery 1.7+
$('#container').on('click', 'a.delete', function(e) {
it is faster and more propery way than:
$(document).on('a.delete'...
or:
$('body').delegate('a.delete'...
or:
$(document).delegate('a.delete'...

jQuery Issue: functions won't work on newly created HTML element

I have two functions: one that creates a new <textarea> when a button is clicked, and a second function that performs an action when the <textarea> is clicked (or blurred, changed, etc.) That second function selects elements based on a class name. It seems that the second function only works on those matching elements that existed when the page was loaded, but it will not activate on any newly created <textarea> elements. Can anyone figure out why and how to fix this? You'll find the code below. Thanks. --Jake
$('#add').click(function() {
$(this).before("<textarea class='test'></textarea>")
})
$('.test').blur(function () {
alert('just a test')
})
The textarea you create isn't around at the time jQuery assigns the action to elements tagged with the .test class. You'll need the live() function to make this work as desired.
$('.test').live('blur', function () {
alert('just a test')
});
Now any element tagged with .test will automatically bind the specified function on blur no matter when it's created.
You can bind it directly:
$('#add').click(function() {
$(this).before("<textarea class='test'></textarea>").prev().blur(function () {
alert('just a test');
});
});
Or place use jQuery's .delegate() method to place a handler on the parent of #add.
$('#add').click(function() {
$(this).before("<textarea class='test'></textarea>")
}).parent().delegate('.test','blur',function() {
alert('just a test');
});
This is a more efficient approach than using .live().

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