I have this event handler from kendo's drag and drop UI and I've assigned it to a variable, lets say e.
I'm trying to select divs that have ID's containing a certain string. I know the syntax for that when continuing from classic jQuery selectors, i.e.
$('select div[id*="whatever"]')
But can I do this off of a variable that contains a DOM element? I know this is a rather simple question but google has thus far been unable to help me.
If you want to filter a preexisting jQuery result, you can go with this:
var $allDivs = $("div"),
$certainDivs = $allDivs.filter("[id*='whatever']");
I believe you might want .find
// returns all DOM elements that
// (1) are descendants of e
// (2) match the selector
e.find("selector");
If e isn't wrapped with jQuery, you might need to do $(e) instead.
Related
I have common jQuery function and two div tags. Both div tags have different names but both containing elements of identical ids now i want to use this common Jquery function for them both?
I have implemented common function but it's not working for both.
Here's link to my jsfiddle -jsfiddle.net/xS7zF/1/
In my jsfiddle there are two div tags namely example1 and example2 and both tags have elements of identical ids. Function is working fine for first div but not for second.
please help me to sort out this.
Yeah, under the hood, jQuery selection on an ID will use the Document.GetElementById() function implemented by the browser, which is really fast, but (i guess depending on the browser) will stop after it finds the first element, since ID's should be unique and no further searching is needed after the first one is found.
For instance, rename the divs with id="eb" to class="eb" and you can still target specific elements using $("#example1 .eb") and $("#example2 .eb")
UPDATE:
Using your new Fiddle I created this: http://jsfiddle.net/xS7zF/5/
I cleaned up a lot of code and hopefully you can see what I have done. I changed all elements that appear twice from id to class. Now, when you attach an event to an element using $(".classname").click(), it attaches to all the elements. In the handler function where you set HTML and do your show()/hide(), you don't target a specific element using it's ID, but you find it relative to the element that does the event. You can do this using parent(), parentsUntil(), next(), find(), etc. Check jQuery docs for all possibilities. So for instance, the change-handler attaches to all inputs with name=Assets. But instead of doing $("#b1").show(), I go to the parent of the specific input that fires using $(this).parent(). Then I find the element with a class=".b1", which it will only find the one that is next to this specific input and I set the HTML to just that element.
Since there is another input, the same actions happen when THAT input changes, but instead it finds IT's parent, and finds the element with class=".b1" that is next to IT. So both divs with input are contained since they act on elements relative to itself and not across the document.
For extra fun and to show you how flexible this way of programming is, here is a fiddle with the Javascript-code unchanged, but with the exact same question-div copied 8 times. No matter how many times you repeat this, the same code will act on as many divs as you create since everything works relative. http://jsfiddle.net/xS7zF/7/
Hopefully this helps, the rest is up to you!
ID's must be unique, you should not repeat them. You could replace id with class and in the jQuery function do (".ub").each() or manually referencing the object using eq(x). e.g. (".ub").eq(1).
You shouldn't assign same id's to different elements.
You CAN but you SHOULDN'T. Instead of giving the same id, use class
IDs must be unique, try fix this, change to classes.
You can try something like this:
$("div div:first-child")
instead of
$("#eb")
But depends of the rest of your page code. So, change to classes first and use
$(".eb")
when jQuery / javascript find the first ID it would ignore the rest, please read more about it
http://www.w3schools.com/tags/att_global_id.asp
This question is related to performance.
If I use a selector like the following
$('#myID a') // Does this find #myID and filter by a?
Or should I write the statement like this?
$('#myID').find('a')
I'm not sure if jQuery is smart enough to execute this statement using the ID first or if it operates exactly like CSS and reads right to left. It's not such a big deal using tags but when you run something like
$('#myID .myClass')
It makes a HUGE difference in performance.
From a NetTuts article: http://net.tutsplus.com/tutorials/javascript-ajax/quick-tip-think-right-to-left-with-jquery/
As an example, if Sizzle comes across a selector like $('#box p'),
it’s true that it works right-to-left, but there’s also a quick regex
optimization that will first determine whether the first section of
the selector is an id. If so, it’ll use that as the context, when
searching for the paragraph tags.
Relevant comment from SizzleJS:
// Take a shortcut and set the context if the root selector is an ID
// (but not if it'll be faster if the inner selector is an ID)
When an Id is in the selector. jQuery will first execute document.getElementById then begin filtering for child elements.
basically this is why it is never a great idea to use just attribute or class selectors $('.someclass') or $('[name=myname]') without being more specific. Because it causes the code to traverse the DOM and look at every element to find that class.
By just adding a tagname to the same selector $('div.someclass') or $('div.[name=myname]') you improve efficiency becuase it will first run. document.getElementsByTagName narrowing the number of elements to search.
I have a form, which I want to iterate through. I want to show one fieldset at a time, and then show a "next" and "back" button to go to the next section.
I'm assuming that I start with $('fieldset'); but how do I access individual elements thereafter?
$("fieldset")[i] does not seem to work.
How would I accomplish that with jQuery?
I don't necessarily recommend this, but:
$($('.fieldset')[i]).css(...)
Should work.
If you wrap each call to $('.fieldset')[i] in a new JQuery selector, you create a new JQuery object out of that single item. JQuery objects have the method css that you want. Regular dom objects do not. (That's what you get with $('.fieldset')[i])
From the jQuery documentation:
How do I pull a native DOM element from a jQuery object?
A jQuery object is an array-like
wrapper around one or more DOM
elements. To get a reference to the
actual DOM elements (instead of the
jQuery object), you have two options.
The first (and fastest) method is to
use array notation:
$('#foo')[0]; // equivalent to
document.getElementById('foo') The
second method is to use the get
function:
$('#foo').get(0); // identical to
above, only slower You can also call
get without any arguments to retrieve
a true array of DOM elements.
To get a jQuery wrapper back around the DOM element you just extracted, rewrap it like so:
$( $('#foo')[0] ) //now it's ajQuery element again.
$("fieldset").each(function() {
// code, applied for each fieldset
})
I have a form with several spans with id="myid". I'd like to be able to remove all elements with this id from the DOM, and I think jQuery is the best way to do it. I figured out how to use the $.remove() method to remove one instance of this id, by simply doing:
$('#myid').remove()
but of course that only removes the first instance of myid. How do I iterate over ALL instances of myid and remove them all? I thought the jQuery $.each() method might be the way, but I can't figure out the syntax to iterate over all instances of myid and remove them all.
If there's a clean way to do this with regular JS (not using jQuery) I'm open to that too. Maybe the problem is that id's are supposed to be unique (i.e. you're not supposed to have multiple elements with id="myid")?
.remove() should remove all of them. I think the problem is that you're using an ID. There's only supposed to be one HTML element with a particular ID on the page, so jQuery is optimizing and not searching for them all. Use a class instead.
All your elements should have a unique IDs, so there should not be more than one element with #myid
An "id" is a unique identifier. Each time this attribute is used in a document it must have a different value. If you are using this attribute as a hook for style sheets it may be more appropriate to use classes (which group elements) than id (which are used to identify exactly one element).
Neverthless, try this:
$("span[id=myid]").remove();
id of DOM element shout be unique. Use class instead (<span class='myclass'>).
To remove all span with this class:
$('.myclass').remove()
if you want to remove all elements with matching ID parts, for example:
<span id='myID_123'>
<span id='myID_456'>
<span id='myID_789'>
try this:
$("span[id*=myID]").remove();
don't forget the '*' - this will remove them all at once - cheers
Working Demo
The cleanest way to do it is by using html5 selectors api, specifically querySelectorAll().
var contentToRemove = document.querySelectorAll("#myid");
$(contentToRemove).remove();
The querySelectorAll() function returns an array of dom elements matching a specific id. Once you have assigned the returned array to a var, then you can pass it as an argument to jquery remove().
You should be using a class for multiple elements as an id is meant to be only a single element. To answer your question on the .each() syntax though, this is what it would look like:
$('#myID').each(function() {
$(this).remove();
});
Official jQuery documentation here.
As already said, only one element can have a specific ID. Use classes instead. Here is jQuery-free version to remove the nodes:
var form = document.getElementById('your-form-id');
var spans = form.getElementsByTagName('span');
for(var i = spans.length; i--;) {
var span = spans[i];
if(span.className.match(/\btheclass\b/)) {
span.parentNode.removeChild(span);
}
}
getElementsByTagName is the most cross-browser-compatible method that can be used here. getElementsByClassName would be much better, but is not supported by Internet Explorer <= IE 8.
Working Demo
I'm a guy used to mootools' way of chaining selectors, and I can't seem to find anywhere how to do the same in jQuery.
Suppose I have a select element in the selectObj variable. What I need is to get the last option in that select.
In mootools I would have done something like:
var option = $(selectObj).getElement('nth-child(last)')
Can I do something similar, or what is the way of getting that last option in jQuery?
PS. I know about the parent > child selector, but I can't really use it because I don't know what selector has been used to get the select. I only have the resulting element.
$(selectObj).find(':last')
You can use find to perform another query within the current query.
In general, you can check out the Selectors and Traversal pages on jQuery docs when you're trying to figure out how to select something.
var option = $(selectObj).children(":last");
will return the last child of any element
You can also use .last() for this purpose.
jQuery has the :last Selector
$("tr:last").stuff()
Will do stuff to the last row in a table.