Develop Reference

Get CSS property from a dynamically added element [duplicate]

How do I toggle the visibility of an element using .hide(), .show(), or .toggle()?
How do I test if an element is visible or hidden?

Since the question refers to a single element, this code might be more suitable:
// Checks CSS content for display:[none|block], ignores visibility:[true|false]
$(element).is(":visible");
// The same works with hidden
$(element).is(":hidden");
It is the same as twernt's suggestion, but applied to a single element; and it matches the algorithm recommended in the jQuery FAQ.
We use jQuery's is() to check the selected element with another element, selector or any jQuery object. This method traverses along the DOM elements to find a match, which satisfies the passed parameter. It will return true if there is a match, otherwise return false.

You can use the hidden selector:
// Matches all elements that are hidden
$('element:hidden')
And the visible selector:
// Matches all elements that are visible
$('element:visible')

if ( $(element).css('display') == 'none' || $(element).css("visibility") == "hidden"){
// 'element' is hidden
}
The above method does not consider the visibility of the parent. To consider the parent as well, you should use .is(":hidden") or .is(":visible").
For example,
<div id="div1" style="display:none">
<div id="div2" style="display:block">Div2</div>
</div>
The above method will consider div2 visible while :visible not. But the above might be useful in many cases, especially when you need to find if there is any error divs visible in the hidden parent because in such conditions :visible will not work.

None of these answers address what I understand to be the question, which is what I was searching for, "How do I handle items that have visibility: hidden?". Neither :visible nor :hidden will handle this, as they are both looking for display per the documentation. As far as I could determine, there is no selector to handle CSS visibility. Here is how I resolved it (standard jQuery selectors, there may be a more condensed syntax):
$(".item").each(function() {
if ($(this).css("visibility") == "hidden") {
// handle non visible state
} else {
// handle visible state
}
});

From How do I determine the state of a toggled element?
You can determine whether an element is collapsed or not by using the :visible and :hidden selectors.
var isVisible = $('#myDiv').is(':visible');
var isHidden = $('#myDiv').is(':hidden');
If you're simply acting on an element based on its visibility, you can just include :visible or :hidden in the selector expression. For example:
$('#myDiv:visible').animate({left: '+=200px'}, 'slow');

Often when checking if something is visible or not, you are going to go right ahead immediately and do something else with it. jQuery chaining makes this easy.
So if you have a selector and you want to perform some action on it only if is visible or hidden, you can use filter(":visible") or filter(":hidden") followed by chaining it with the action you want to take.
So instead of an if statement, like this:
if ($('#btnUpdate').is(":visible"))
{
$('#btnUpdate').animate({ width: "toggle" }); // Hide button
}
Or more efficient, but even uglier:
var button = $('#btnUpdate');
if (button.is(":visible"))
{
button.animate({ width: "toggle" }); // Hide button
}
You can do it all in one line:
$('#btnUpdate').filter(":visible").animate({ width: "toggle" });

The :visible selector according to the jQuery documentation:
They have a CSS display value of none.
They are form elements with type="hidden".
Their width and height are explicitly set to 0.
An ancestor element is hidden, so the element is not shown on the page.
Elements with visibility: hidden or opacity: 0 are considered to be visible, since they still consume space in the layout.
This is useful in some cases and useless in others, because if you want to check if the element is visible (display != none), ignoring the parents visibility, you will find that doing .css("display") == 'none' is not only faster, but will also return the visibility check correctly.
If you want to check visibility instead of display, you should use: .css("visibility") == "hidden".
Also take into consideration the additional jQuery notes:
Because :visible is a jQuery extension and not part of the CSS specification, queries using :visible cannot take advantage of the performance boost provided by the native DOM querySelectorAll() method. To achieve the best performance when using :visible to select elements, first select the elements using a pure CSS selector, then use .filter(":visible").
Also, if you are concerned about performance, you should check Now you see me… show/hide performance (2010-05-04). And use other methods to show and hide elements.

How element visibility and jQuery works;
An element could be hidden with display:none, visibility:hidden or opacity:0. The difference between those methods:
display:none hides the element, and it does not take up any space;
visibility:hidden hides the element, but it still takes up space in the layout;
opacity:0 hides the element as "visibility:hidden", and it still takes up space in the layout; the only difference is that opacity lets one to make an element partly transparent;
if ($('.target').is(':hidden')) {
$('.target').show();
} else {
$('.target').hide();
}
if ($('.target').is(':visible')) {
$('.target').hide();
} else {
$('.target').show();
}
if ($('.target-visibility').css('visibility') == 'hidden') {
$('.target-visibility').css({
visibility: "visible",
display: ""
});
} else {
$('.target-visibility').css({
visibility: "hidden",
display: ""
});
}
if ($('.target-visibility').css('opacity') == "0") {
$('.target-visibility').css({
opacity: "1",
display: ""
});
} else {
$('.target-visibility').css({
opacity: "0",
display: ""
});
}
Useful jQuery toggle methods:
$('.click').click(function() {
$('.target').toggle();
});
$('.click').click(function() {
$('.target').slideToggle();
});
$('.click').click(function() {
$('.target').fadeToggle();
});

This works for me, and I am using show() and hide() to make my div hidden/visible:
if( $(this).css('display') == 'none' ){
/* your code goes here */
} else {
/* alternate logic */
}

You can also do this using plain JavaScript:
function isRendered(domObj) {
if ((domObj.nodeType != 1) || (domObj == document.body)) {
return true;
}
if (domObj.currentStyle && domObj.currentStyle["display"] != "none" && domObj.currentStyle["visibility"] != "hidden") {
return isRendered(domObj.parentNode);
} else if (window.getComputedStyle) {
var cs = document.defaultView.getComputedStyle(domObj, null);
if (cs.getPropertyValue("display") != "none" && cs.getPropertyValue("visibility") != "hidden") {
return isRendered(domObj.parentNode);
}
}
return false;
}
Notes:
Works everywhere
Works for nested elements
Works for CSS and inline styles
Doesn't require a framework

I would use CSS class .hide { display: none!important; }.
For hiding/showing, I call .addClass("hide")/.removeClass("hide"). For checking visibility, I use .hasClass("hide").
It's a simple and clear way to check/hide/show elements, if you don't plan to use .toggle() or .animate() methods.

Demo Link
$('#clickme').click(function() {
$('#book').toggle('slow', function() {
// Animation complete.
alert($('#book').is(":visible")); //<--- TRUE if Visible False if Hidden
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="clickme">
Click here
</div>
<img id="book" src="https://upload.wikimedia.org/wikipedia/commons/8/87/Google_Chrome_icon_%282011%29.png" alt="" width="300"/>
Source (from my blog):
Blogger Plug n Play - jQuery Tools and Widgets: How to See if Element is hidden or Visible Using jQuery

ebdiv should be set to style="display:none;". It works for both show and hide:
$(document).ready(function(){
$("#eb").click(function(){
$("#ebdiv").toggle();
});
});

One can simply use the hidden or visible attribute, like:
$('element:hidden')
$('element:visible')
Or you can simplify the same with is as follows.
$(element).is(":visible")

Another answer you should put into consideration is if you are hiding an element, you should use jQuery, but instead of actually hiding it, you remove the whole element, but you copy its HTML content and the tag itself into a jQuery variable, and then all you need to do is test if there is such a tag on the screen, using the normal if (!$('#thetagname').length).

When testing an element against :hidden selector in jQuery it should be considered that an absolute positioned element may be recognized as hidden although their child elements are visible.
This seems somewhat counter-intuitive in the first place – though having a closer look at the jQuery documentation gives the relevant information:
Elements can be considered hidden for several reasons: [...] Their width and height are explicitly set to 0. [...]
So this actually makes sense in regards to the box-model and the computed style for the element. Even if width and height are not set explicitly to 0 they may be set implicitly.
Have a look at the following example:
console.log($('.foo').is(':hidden')); // true
console.log($('.bar').is(':hidden')); // false
.foo {
position: absolute;
left: 10px;
top: 10px;
background: #ff0000;
}
.bar {
position: absolute;
left: 10px;
top: 10px;
width: 20px;
height: 20px;
background: #0000ff;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="foo">
<div class="bar"></div>
</div>
Update for jQuery 3.x:
With jQuery 3 the described behavior will change! Elements will be considered visible if they have any layout boxes, including those of zero width and/or height.
JSFiddle with jQuery 3.0.0-alpha1:
http://jsfiddle.net/pM2q3/7/
The same JavaScript code will then have this output:
console.log($('.foo').is(':hidden')); // false
console.log($('.bar').is(':hidden')); // false

expect($("#message_div").css("display")).toBe("none");

$(document).ready(function() {
if ($("#checkme:hidden").length) {
console.log('Hidden');
}
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="checkme" class="product" style="display:none">
<span class="itemlist"><!-- Shows Results for Fish --></span> Category:Fish
<br>Product: Salmon Atlantic
<br>Specie: Salmo salar
<br>Form: Steaks
</div>

To check if it is not visible I use !:
if ( !$('#book').is(':visible')) {
alert('#book is not visible')
}
Or the following is also the sam, saving the jQuery selector in a variable to have better performance when you need it multiple times:
var $book = $('#book')
if(!$book.is(':visible')) {
alert('#book is not visible')
}

Use class toggling, not style editing . . .
Using classes designated for "hiding" elements is easy and also one of the most efficient methods. Toggling a class 'hidden' with a Display style of 'none' will perform faster than editing that style directly. I explained some of this pretty thoroughly in Stack Overflow question Turning two elements visible/hidden in the same div.
JavaScript Best Practices and Optimization
Here is a truly enlightening video of a Google Tech Talk by Google front-end engineer Nicholas Zakas:
Speed Up Your Javascript (YouTube)

After all, none of examples suits me, so I wrote my own.
Tests (no support of Internet Explorer filter:alpha):
a) Check if the document is not hidden
b) Check if an element has zero width / height / opacity or display:none / visibility:hidden in inline styles
c) Check if the center (also because it is faster than testing every pixel / corner) of element is not hidden by other element (and all ancestors, example: overflow:hidden / scroll / one element over another) or screen edges
d) Check if an element has zero width / height / opacity or display:none / visibility:hidden in computed styles (among all ancestors)
Tested on
Android 4.4 (Native browser/Chrome/Firefox), Firefox (Windows/Mac), Chrome (Windows/Mac), Opera (Windows Presto/Mac WebKit), Internet Explorer (Internet Explorer 5-11 document modes + Internet Explorer 8 on a virtual machine), and Safari (Windows/Mac/iOS).
var is_visible = (function () {
var x = window.pageXOffset ? window.pageXOffset + window.innerWidth - 1 : 0,
y = window.pageYOffset ? window.pageYOffset + window.innerHeight - 1 : 0,
relative = !!((!x && !y) || !document.elementFromPoint(x, y));
function inside(child, parent) {
while(child){
if (child === parent) return true;
child = child.parentNode;
}
return false;
};
return function (elem) {
if (
document.hidden ||
elem.offsetWidth==0 ||
elem.offsetHeight==0 ||
elem.style.visibility=='hidden' ||
elem.style.display=='none' ||
elem.style.opacity===0
) return false;
var rect = elem.getBoundingClientRect();
if (relative) {
if (!inside(document.elementFromPoint(rect.left + elem.offsetWidth/2, rect.top + elem.offsetHeight/2),elem)) return false;
} else if (
!inside(document.elementFromPoint(rect.left + elem.offsetWidth/2 + window.pageXOffset, rect.top + elem.offsetHeight/2 + window.pageYOffset), elem) ||
(
rect.top + elem.offsetHeight/2 < 0 ||
rect.left + elem.offsetWidth/2 < 0 ||
rect.bottom - elem.offsetHeight/2 > (window.innerHeight || document.documentElement.clientHeight) ||
rect.right - elem.offsetWidth/2 > (window.innerWidth || document.documentElement.clientWidth)
)
) return false;
if (window.getComputedStyle || elem.currentStyle) {
var el = elem,
comp = null;
while (el) {
if (el === document) {break;} else if(!el.parentNode) return false;
comp = window.getComputedStyle ? window.getComputedStyle(el, null) : el.currentStyle;
if (comp && (comp.visibility=='hidden' || comp.display == 'none' || (typeof comp.opacity !=='undefined' && comp.opacity != 1))) return false;
el = el.parentNode;
}
}
return true;
}
})();
How to use:
is_visible(elem) // boolean

Example of using the visible check for adblocker is activated:
$(document).ready(function(){
if(!$("#ablockercheck").is(":visible"))
$("#ablockermsg").text("Please disable adblocker.").show();
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="ad-placement" id="ablockercheck"></div>
<div id="ablockermsg" style="display: none"></div>
"ablockercheck" is a ID which adblocker blocks. So checking it if it is visible you are able to detect if adblocker is turned On.

$(document).ready(function() {
var visible = $('#tElement').is(':visible');
if(visible) {
alert("visible");
// Code
}
else
{
alert("hidden");
}
});
<script src="https://code.jquery.com/jquery-1.10.2.js"></script>
<input type="text" id="tElement" style="display:block;">Firstname</input>

You need to check both... Display as well as visibility:
if ($(this).css("display") == "none" || $(this).css("visibility") == "hidden") {
// The element is not visible
} else {
// The element is visible
}
If we check for $(this).is(":visible"), jQuery checks for both the things automatically.

Simply check visibility by checking for a boolean value, like:
if (this.hidden === false) {
// Your code
}
I used this code for each function. Otherwise you can use is(':visible') for checking the visibility of an element.

Because Elements with visibility: hidden or opacity: 0 are considered visible, since they still consume space in the layout (as described for jQuery :visible Selector) - we can check if element is really visible in this way:
function isElementReallyHidden (el) {
return $(el).is(":hidden") || $(el).css("visibility") == "hidden" || $(el).css('opacity') == 0;
}
var booElementReallyShowed = !isElementReallyHidden(someEl);
$(someEl).parents().each(function () {
if (isElementReallyHidden(this)) {
booElementReallyShowed = false;
}
});

But what if the element's CSS is like the following?
.element{
position: absolute;left:-9999;
}
So this answer to Stack Overflow question How to check if an element is off-screen should also be considered.

A function can be created in order to check for visibility/display attributes in order to gauge whether the element is shown in the UI or not.
function checkUIElementVisible(element) {
return ((element.css('display') !== 'none') && (element.css('visibility') !== 'hidden'));
}
Working Fiddle

Also here's a ternary conditional expression to check the state of the element and then to toggle it:
$('someElement').on('click', function(){ $('elementToToggle').is(':visible') ? $('elementToToggle').hide('slow') : $('elementToToggle').show('slow'); });

if($('#postcode_div').is(':visible')) {
if($('#postcode_text').val()=='') {
$('#spanPost').text('\u00a0');
} else {
$('#spanPost').text($('#postcode_text').val());
}

jQuery cannot assign to a function result

I am getting the error in the title above in the following code:
$j(".table").delegate('td','click', function(e) {
//alert($j(this).parent().css('background-color'));
if ($j(this).parent().css('background-color') == 'transparent')
$j(this).parent().css('background-color') = '#eee';
else {
$j(this).parent().css('background-color') = 'transparent';
}
});
I don't understand why I'd be getting this error, as I have made sure I am using the assignment operator == to compare the strings

There are 2 issues with your question: first one is already answered by #Mike Vranckx, the correct usage of .css() setter is passing a second argument to set as value.
The other problem is that your condition will never be true, I'll address it in this answer. If you fix it in the way I suggest, you won't be needing .css().
Computed CSS values, which are returned from getComputedStyle/jQuery's .css(), are not exactly what you've authored in your code -- they suffer transformations when parsed into the CSSOM.
For instance, in Chrome:
body { background-color: transparent; }
console.log( $('body').css('background-color') ); //returns "rgba(0, 0, 0, 0)"
See for yourself.
That's why your $(...).('background-color') == 'transparent' condition is always false.
The most clean and cross-browser solution is to apply styling with classes (.addClass(), removeClass(), toggleClass()) and do conditional checks with .hasClass().
In your case though, .toggleClass should suffice. Here's a simple way to write your logic (fiddle):
$j(".table").on('click', 'td', function() {
$j(this).parent().toggleClass('bg-gray');
});
.bg-gray {
background: #eee;
}

To set / change the background-color property, you need to pass it as a second argument:
$j(this).parent().css('background-color', '#eee');

While compare using background color better to use rgba like this
$j(this).parent().css('background-color', 'rgb(0,0,0)');

To assign value to css, pass the value as a second argument.
The below line will change to
$j(this).parent().css('background-color') = '#eee';
The following Line
$j(this).parent().css('background-color','#eee');

It would be cleaner, faster, and easier to modify to use a CSS class :
.table td { background-color: transparent; }
.foo { background-color: #EEE; }
And
$j( '.table' ).delegate( 'td', 'click', function() {
$( this ).toggleClass( 'foo' );
});
Also avoid using reserved words like "table" for class names, it's confusing.

How do I iterate through div's child elements and hide them?

I have a div that have a few elements that I want to hide, on users request. Those elements have a particular background color. The call of the function is working (it is associated to a checkbox) but it just doesnt do what i want. Actually, it does nothing. This is what I've got:
function toogleDisplay()
{
var kiddos= document.getElementById('external-events').childNodes; //my div
for(i=0; i < kiddos.length; i++)
{
var a=kiddos[i];
if (a.style.backgroundColor=="#A2B5CD")
{
if (a.style.display!="none")
{
a.style.display='none';
}
else
{
a.style.display='block';
}
}
}
}
What am I doing wrong?

An element's background colour is converted to rgb() (or rgba()) format internally.
But that aside, assuming $ is jQuery (you haven't tagged your question so I don't know!) then a is a jQuery object, which does not have a style property. It looks like you just wanted var a = kiddos[i];.
It is more reliable to use a specific class name instead.

You re wrapping your kiddos[i] in a jquery-object $(kiddos[i]) and then try to access the normal properties of a html-dom-objekt.
You have 2 possibilities:
remove the $()
use jquery-access to the properties
a.css('display', none); // or just a.hide();
Additionally you cant check for '#123456' since the color is transformed. Check (#Niet the Dark Absol)s answer for this

I would suggest adding a class to the elements you want to check. Then instead of trying to use background, you can do
$(kiddos[i]).hasClass('myclass')
or for a very efficient way, you can do it in one line of code.
function toogleDisplay()
{
$('.myclass').toggle(); //this will toggle hide/show
}
The divs would look like this
<div class='myclass'>Content</div>
EDIT - to do it without modifying existing html. I also think the rbg color should be rgb(162, 181, 205) if im not mistaken.
You can try something like this. Its based off the following link
Selecting elements with a certain background color
function toogleDisplay()
{
$('div#external-events').filter(function() {
var match = 'rgb(162, 181, 205)'; // should be your color
return ( $(this).css('background-color') == match );
}).toggle()
}

Your jquery selection of a is causing issues. Unwrap the $() from that and you should be fine.
Also you could end up selecting text nodes that wont have a style property. You should check that the style property exists on the node before trying to access background, display, etc.
Use a class instead of a background and check for that instead.

i think you need to see if the 'nodeType' is an element 'a.nodeType == 1' see Node.nodeType then it will work over multiple lines
var kiddos= document.getElementById('external-events').childNodes; //my div
for(i=0; i < kiddos.length; i++)
{
var a=kiddos[i];
if (a.nodeType == 1){ // Check the node type
if (a.style.backgroundColor=="red")
{
if (a.style.display!="none")
{
a.style.display='none';
}
else
{
a.style.display='block';
}
}
}
}

I decided to go for another aproach, using the idea of Kalel Wade. All the elements that may be (or not) hidden, already had a class name, which were the same for all elements, fortunately.
here comes the code
function toogleDisplay()
{
var kiddos = document.getElementsByClassName("external-event ui-draggable");
for (var i = 0, len = kiddos.length; i < len; i++) {
var a=kiddos[i];
if (a.style.backgroundColor==="rgb(162, 181, 205)")
{
if (a.style.display!="none")
{
a.style.display='none';
}
else
{
a.style.display='block';
}
}
}
}

Is there a way to find all elements matching a certain style using the DOM?

I want an array of all elements that have fixed position.
This is what I've got so far (mootools code)
$$('*').filter(function(aEl){ return aEl.getStyle('position')=='fixed' });
Is there a more direct way to do this?

not really, what you posted is the best way of doing it.
but if it's something you do more often, I'd consider abstracting it to a pseudo selector:
Selectors.Pseudo.fixed = function(){
return this.getStyle("position") == "fixed";
};
// can now use it as a part of a normal selector:
console.log(document.getElements("div:fixed"));
p.s. this will break in mootools 1.3 as slick uses a different selectors engine.
to make it work in 1.3 do:
Slick.definePseudo('fixed',function() {
return this.getStyle("position") == "fixed";
});
and finally, to make it more versatile so you can look up any CSS property as a part of the selector, you can do something like this:
Selectors.Pseudo.style = function(key) {
var styles = key.split("=");
return styles.length == 2 && this.getStyle(styles[0]) == styles[1];
};
and for mootools 1.3:
Slick.definePseudo('style', function(key) {
var styles = key.split("=");
return styles.length == 2 && this.getStyle(styles[0]) == styles[1];
});
how to use it:
console.log(document.getElements("div:style(position=fixed)"));
http://www.jsfiddle.net/h7JPS/3/

I would suggest you to make a css class
.fixed_pos
{
position: fixed;
}
apply this class to elements that you want and then
$$(".fixed_pos");
That will give you to all the element

jQuery: copying element attributes to another attribute of the same element

I've got a list of links, all in the same class, each with a custom argument ("switch-text"). My script should copy the text of the custom argument to the text of each link and replace it ("Pick A" should become "Pick A Please").
It works fine with only 1 link, but when I add several, they all get switched to the first argument. ("Pick B" should be replaced by "Pick B Please", but it doesn't).
I could probably solve this using each(), but I'm preferably looking for a simple, single jQuery line that does it, and I'm baffled I haven't yet found out how to achieve this.
Can somebody help? Thanks!
<script src="http://code.jquery.com/jquery-latest.min.js"></script>
<script>
$(document).ready(function() {
$(".switcher").text( $(".switcher").attr("switch-text") );
});
</script>
Pick A<br>
Pick B<br>

You should use each to go through all the elements, and use this to always act on the current one.
$(document).ready(function() {
$(".switcher").each(function(){
$(this).text( $(this).attr("switch-text") );
});
});
Demo
Without jQuery
you need:
Dean Edwards document ready
getElementsByClassName
Code:
readyList.push(function() {
var els = getElementsByClassName("switcher");
for ( var i = els.length; i--; ) {
els[i].innerHTML = els[i].getAttribute("switch-text");
}
});
And change Dean's script to execute functions on document.ready:
function init() {
// ...
// do stuff
for ( var i = 0; i < readyList.length; i++ ) {
if ( typeof readyList[i] === "function" ) {
readyList[i]();
}
}
//..
}
That's it. You've saved a lot of bandwidth. :)
Demo without jQuery