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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.

Re-enable links disabled with disable_with

How can I manually re-enable links (not form elements) that get disabled with Rails' disable_with feature?

The call to reenable links is slightly different than form elements. It actually binds a handler to the click event that stops anything else from happening. I was able to figure this out by investigating how the jquery-ujs library.
To reverse this effect, simply use the enableElement method on your jQuery object:
$.rails.enableElement($('a[data-disable-with]'));
With Turbolinks, it also helps to watch for the 'page:change' event instead of window.unload:
$(document).on('page:change', function() {
$.rails.enableElement($('a[data-disable-with]'));
});

A solution I found here:
$(window).unload(function() {
$.rails.enableFormElements($($.rails.formSubmitSelector));
});

Rails has updated their javascript to no longer use jQuery.
You can now re-enable elements with the following (assuming you are still using jQuery):
var selectors = [Rails.linkDisableSelector, Rails.formEnableSelector].join(', ');
$(selectors).each(function() {
Rails.enableElement(this);
})

Hey its quite simple you just need to find button and do
$button = $('#someId')
$.rails.enableElement($button)
$button.removeAttr('disabled')

Based on #DGM solution I ended up with the following code:
$.rails.enableFormElements($disabled_button);
Where:
$disabled_button is the jQuery object for the button disabled by data-disable-with which could be selected like this:
$disabled_button = $('[data-disable-with]');

OK I found this interesting work around (apparently the problem is only in FF)
set :autocomplete => 'off' and now it works. Or one of the other answer might work as well.
ref: https://github.com/rails/jquery-ujs/issues/357

You can use jQuery to remove the data-disable-with attribute that Rails adds to the button:
$('#disabledbutton').removeAttr('data-disable-with');

jquery .live() and .append()

So I'm currently using .append() to add a feature to all of the posts on a webpage, but when additional posts are loaded on the page, the appended features aren't included in the new content — I'm trying to come up with a way to make sure all of the new content has the appended feature too.
$(this).append('<div id="new_feature></div>');
Something like this?
$(this).live().append('<div id="new_feature></div>');
Maybe there's a way to make it constantly appending in a loop perhaps?

There is DOMNodeInserted event:
$('button').click(function() {
$('#appendme').append($('<div class="inner">').text(Math.random()));
})
$('#appendme').on('DOMNodeInserted','.inner',function() {
console.log(this);
});
DEMO
update: this seems not works in IE, try propertychnage event handler also ($('#appendme').on('DOMNodeInserted,propertychange') but i not sure, have no IE to check this right now.
update2: Domnode* seems deprecated according to mdn, they tell to use MutationObserver object instead
update3: seems here is no very crossbrowser solution for MutationEvents, see this answer, so my suggestion would be use code above, if event supported and fallback to setTimeOut or livequery option.
update4:
If you depend only on .append() you can patch jQuery.fn.append() like this:
jQuery.fn.append=function() {
return this.domManip(arguments, true, function( elem ) {
if ( this.nodeType === 1 || this.nodeType === 11 ) {
this.appendChild( elem );
$(elem).trigger('appended');
}
});
};
$('button').click(function() {
$('#appendme').append($('<div class="inner">').text(Math.random()));
})
$('#appendme').on('appended','.inner',function() {
console.log(this);
});
DEMO2
may be more correct is to spoof jQuery.fn.domManip like here

jQuery documentation:
Use of the .live() method is no longer recommended since later versions of jQuery offer better methods that do not have its drawbacks.
You can use setTimeout() function that can check for new <div>s every n milliseconds.
$(function(){
setInterval("Check4NewDivs();",1000);
});
So say this is a div with class="comment newdiv", so when it appears on the page for the first time, it has the class newdiv that will let the function know it was just dynamically created.
function Check4NewDivs(){
$(".comment .newdiv").each(function(){
$(this).append('<div class="new_feature"></div>').removeClass("newdiv");
});
}

It's append not appened.
live is a deprecated event handler. It's not used this way. use on instead.
http://api.jquery.com/live/
So, the following code will run when you click selector.
$(document).on('click', 'selector', function() {
$(this).append('<div id="new_feature></div>');
});

No, there is no standard way to do it like that. There was a proposal of the events that would be fired whenever the DOM elements are inserted etc., but you cannot rely on that.
Instead rely on either:
(preferably) callbacks - just invoke function ensuring existence of such appended snippets, whenever you pull something (but after you successfully pull it from server and insert into DOM, not sooner), or
constant checks - like using in setInterval() or setTimeout(), but this would be unnecessary processing and you will never get instant append, unless you will perform processing-heavy checks all the time,

use the on load function:
$(item).on('load',function(){
$(this).append('<div id="new_feature"></div>');
});
This will add append the item as a callback once the item has been loaded. I would also choose some sort of dynamic ID creator rather than always append stuff with the same ID, but thats just me.

you must bind to an element that already exists on the page. i have written an example where i make appended content live.
DEMO on JSFiddle
HTML
<div id="container">
<div id="features">
</div>
<br />
<a href='#' id='clickme'>click me to add feature</a>
</div>
JS
$(function() {
$('#clickme').on('click', function(e) {
$('#features').append('<div class="new_feature">new feature</div>');
});
$('#features').on('click', '.new_feature', function() {
alert('i am live.');
});
});

How to add touch events to a class?.. prefereably through jquery

How can you do something like the following?
$('.myDivs').ontouchstart(function(){
alert('touch');
})
the only way I appear to be able to implement touch events is using javascript.. like so
document.getElementById('singleDiv').addEventListener("touchstart",touchHandler, false);
However I would like to implement this to a class, rather than an id... therefore is there a way to do it using jquery like the above example?....
I have found the answer:
$('.myDivs').bind('touchstart', function (event) { alert('touch');});
Kind regards J

As of jQuery 1.4.2, the following works fine for me:
$('.classname').live('touchstart', function(e) {
// Do whatever you want here...
});
Or for the latest versions of jQuery:
$('.classname').on('touchstart', function(e) {
// Do whatever you want here...
});

just select the class instead of the id:
document.getElementsByClassName('myClass').addEventListener(...);
please not that this selector will not work in IE. For IE you could use jQuery:
$('.myClass').on("click",function(){});

not work class .numeric after add new input. what do i do?

why after add new input, class .numeric (normal number formatting) in js code not worked?
This way for normal number formatting is right?
What is your suggestion?
i not want use of plugin.
DEMO
$("input:text.numeric").keyup(function () {
$val = $(this).val().match(/[0-9]/g).reverse().join("").match(/[0-9]{1,3}/g).join(",").match(/./g).reverse().join("");
$(this).val($val)
})
With respect

If you add something to the page after it is done loading you will need to use the live() function on your scripts to make them work on the new data.
If you do something like:
$('#container').append('<div class="clickme">The text goes here</div>');
or
$('#container').load('script.php');
...they are both considered adding to the page.
Using live(), your code would become:
$("input:text.numeric").live('keyup', function () {
$val = $(this).val().match(/[0-9]/g).reverse().join("").match(/[0-9]{1,3}/g).join(",").match(/./g).reverse().join("");
$(this).val($val)
});
Read more here: http://api.jquery.com/live/

You need a future-proof event observer. Since the keyup bind is assigned to existing nodes, any nodes you create afterwards will not be bound to that event. You need to use live or delegate
Change
$("input:text.numeric").keyup(function () {
to
$("input:text.numeric").live('keyup',function () {
or
$('.find_input').delegate('input:text.numeric','keyup',function () {
delegate() is much more resource-friendly than live() but you need to know the parent ahead of time. In your example, I'd recommend it.
Working demo: http://jsfiddle.net/AlienWebguy/zgWr3/4/

Use the delegate()[docs] method to bind the handler to the .column container.
Example: http://jsfiddle.net/zgWr3/3/
$('.column').delegate("input.numeric:text",'keyup',function () {
$val = $(this).val().match(/[0-9]/g).reverse().join("").match(/[0-9]{1,3}/g).join(",").match(/./g).reverse().join("");
$(this).val($val)
});
This way, any "input.numeric:text" elements inside of .column will invoke the handler irrespective of when they're added to the DOM.
I also changed the selector around a little. Seems more understandable to me.