I am trying to disable a button dynamically based on a data attribute that's present on the body, code looks sort of like this:
<body data-online="true">
<button disabled></button>
</body>
What I want is to set the pseudoclass disabled based on the value of the body's data attribute. I'm looking for the simplest possible way to do this. I know that conventionally this would be done asynchronously with JS, but for annoying reasons I have no direct control over I would prefer another way. I'm wondering if it's possible to set the pseudoclass directly through CSS or HTML in some way?
I honestly don't this it is possible to achieve this without any JavaScript since the disabled properly is a boolean attribute.
You'll need at least to grab the element using JavaScript and conditionally apply the disabled attribute. As on the code below:
function checkButtonDisabled() {
const body = document.querySelector('body');
const button = document.querySelector('#btn')
const buttonIsDisabled = body.getAttribute('data-online') === 'true'
if (buttonIsDisabled) {
button.setAttribute("disabled", true)
return
}
button.removeAttribute("disabled")
}
checkButtonDisabled()
Although, If your intention is also to style it, you could use the selector below or some variant that could suit better for you:
body[data-online="true"] > button {
/* Your styles here */
}
you could check this article also which explains attribute selectors.
Related
I am trying to create an array of 'li' elements that hold icons for app level navigation. I have a css class "is-active" that highlights the active 'li' element in the list indicating the active location in the nav schema. I expect Maquette JS to render the appropriate icon as 'highlighted' when it is selected by the end user. I am trying to use the classes:{} property as such:
"classes": this._activeNavElementId === navItem.id ? "nav-menu-item nav-menu-item-is-active" : "nav-menu-item", ...
Clearly this is an improper use. The tutorial provides an example where the boolean determines if a class is in the classList; however, I actually need to use classList A if true or classList B if false.
Having a hard time finding good examples of maquettejs conditional css. Any thoughts?
Conditional CSS classes work as follows:
h("li.nav-menu-item", {
"classes": {
"nav-menu-item-is-active": this._activeNavElementId === navItem.id
}
}
Can I edit a HTML-tag's CSS using DART?
I have done some searching but I couldn't really find out how to do it, or if it even is possible.
The reason to do this because I would like to change a button's location on a page.
You can change or view css properties through Element.style. The Element.style is an instance of CssStyleDeclaration. You can do the following:
Element element = document.querySelector("div")
..style // edit any of the properties of this variable
..style.background = "orange";
I guess you are looking for something like
var el = document.querySelector('.somediv');
// or '#someid' or other CSS selector to get hold of an element
el.style.color = 'blue';
You may want to look at the dart class CssStyleSheet which can grab a sheet and delete, insert and add rules. You need to know the index of the rule in the style sheet.
If I create an HTML anchor tag and set the disabled attribute to true, I get different behaviors in different browsers (surprise! surprise!).
I created a fiddle to demonstrate.
In IE9, the link is grayed out and does not transfer to the HREF location.
In Chrome/FF/Safari, the link is the normal color and will transfer to the HREF location.
What should the correct behavior be? Is IE9 rendering this incorrectly and I should implement some CSS and javascript to fix it; or is Chrome/FF/Safari not correct and will eventually catch up?
Thanks in advance.
IE appears to be acting incorrectly in this instance.
See the HTML5 spec
The IDL attribute disabled only applies to style sheet links. When the
link element defines a style sheet link, then the disabled attribute
behaves as defined for the alternative style sheets DOM. For all other
link elements it always return false and does nothing on setting.
http://dev.w3.org/html5/spec/Overview.html#the-link-element
The HTML4 spec doesn't even mention disabled
http://www.w3.org/TR/html401/struct/links.html#h-12.2
EDIT
I think the only way to get this effect cross-browser is js/css as follows:
#link{
text-decoration:none;
color: #ccc;
}
js
$('#link').click(function(e){
e.preventDefault();
});
Example: http://jsfiddle.net/jasongennaro/QGWcn/
I had to fix this behavior in a site with a lot of anchors that were being enabled/disabled with this attribute according to other conditions, etc. Maybe not ideal, but in a situation like that, if you prefer not to fix each anchor's code individually, this will do the trick for all the anchors:
$('a').each(function () {
$(this).click(function (e) {
if ($(this).attr('disabled')) {
e.preventDefault();
e.stopImmediatePropagation();
}
});
var events = $._data ? $._data(this, 'events') : $(this).data('events');
events.click.splice(0, 0, events.click.pop());
});
And:
a[disabled] {
color: gray;
text-decoration: none;
}
disabled is an attribute that only applies to input elements per the standards. IE may support it on a, but you'll want to use CSS/JS instead if you want to be standards compliant.
The JQuery answer didn't work for me because my anchor tag is on a form and on my forms I use asp field validators and they just weren't playing nice. This led me to finding a pretty simple answer that doesn't require JQuery or CSS...
<a id="btnSubmit" href="GoSomePlace">Display Text</a>
You can disable the element and it should behave as input types do. No CSS needed. This worked for me in chrome and ff.
function DisableButton() {
var submitButton = document.getElementById("btnSubmit");
if (submitButton != null) {
submitButton.setAttribute('disabled', 'disabled');
}
}
Of course you'll be doing a loop to disable all anchor tags in the DOM but my example shows how to do it for just one specific element. You want to make sure you're getting the right client id of your element but this worked for me, on more than one occasion. This will also work on asp:LinkButtons which end up being anchor tag elements when rendered in the browser.
I am creating a website and i want to allow personalization to individual users upto some extent like changing font family, background color etc. The problem with this is that, my default css file that i load has already default classes for everything. Now when i fetch the background color from my database, then if there is null value for background color then default css class of mystylesheet.css should be loaded and if the value is not null, then i want to override this with my default css. How is it possible? Thanks in advance :)
Load the default stylesheat in a style tag, and put your dynamic styles in a style tag after that.
Which style to use when different styles target the same element is determined by specificity, and if the selectors are the same, by order. The style that is found last is used.
The approach mentioned by zaf would require that you reload the page when you want to switch styles sheets. What I find to be a better approach is to add a classname to the body
if you have the option of using javascript
<body class="theme-1">
<div class="main"><div>
</body>
Then each of your style sheets should contain the theme name in the declarations:
--theme1.css
.theme-1 div.main {
background-color: #eee
}
--theme2.css
.theme-2 div.main {
background-color: #f30
}
To switch style sheets, you just remove the old theme name and add the theme you want to use.
Then you can even add style sheets dynamically if you provide an interface for the user to customize the look and feel of your page.
New Improved Answer:
I just found a nice solution implemented by the folks at extjs. It involves loading all the stylesheets you want using <link> tags. The trick is that you can set a disabled property on the link element which will cause it not to apply.
For an example, use firebug and look at
http://www.extjs.com/deploy/dev/examples/themes/index.html
Look for styleswitcher.js and look at the function setActiveStyleSheet
function setActiveStyleSheet(title) {
var i,
a,
links = document.getElementsByTagName("link"),
len = links.length;
for (i = 0; i < len; i++) {
a = links[i];
if (a.getAttribute("rel").indexOf("style") != -1 && a.getAttribute("title")) {
a.disabled = true;
if (a.getAttribute("title") == title) a.disabled = false;
}
}
}
EDIT:
Reason for CSS property precedence?
One way is to produce the css file dynamically from a php script.
You would include the file like:
<link rel="stylesheet" type="text/css" href="css.php">
And the css.php file would look something like this:
<?php
header('Content-type: text/css');
// whatever you want to ouput depending on the user
?>
I'm looking for a definitive list of HTML elements which are allowed to take focus, i.e. which elements will be put into focus when focus() is called on them?
I'm writing a jQuery extension which works on elements that can be brought into focus. I hope the answer to this question will allow me to be specific about the elements I target.
There isn't a definite list, it's up to the browser. The only standard we have is DOM Level 2 HTML, according to which the only elements that have a focus() method are
HTMLInputElement, HTMLSelectElement, HTMLTextAreaElement and HTMLAnchorElement. This notably omits HTMLButtonElement and HTMLAreaElement.
Today's browsers define focus() on HTMLElement, but an element won't actually take focus unless it's one of:
HTMLAnchorElement/HTMLAreaElement with an href
HTMLInputElement/HTMLSelectElement/HTMLTextAreaElement/HTMLButtonElement but not with disabled (IE actually gives you an error if you try), and file uploads have unusual behaviour for security reasons
HTMLIFrameElement (though focusing it doesn't do anything useful). Other embedding elements also, maybe, I haven't tested them all.
Any element with a tabindex
There are likely to be other subtle exceptions and additions to this behaviour depending on browser.
Here I have a CSS-selector based on bobince's answer to select any focusable HTML element:
a[href]:not([tabindex='-1']),
area[href]:not([tabindex='-1']),
input:not([disabled]):not([tabindex='-1']),
select:not([disabled]):not([tabindex='-1']),
textarea:not([disabled]):not([tabindex='-1']),
button:not([disabled]):not([tabindex='-1']),
iframe:not([tabindex='-1']),
[tabindex]:not([tabindex='-1']),
[contentEditable=true]:not([tabindex='-1'])
{
/* your CSS for focusable elements goes here */
}
or a little more beautiful in SASS:
a[href],
area[href],
input:not([disabled]),
select:not([disabled]),
textarea:not([disabled]),
button:not([disabled]),
iframe,
[tabindex],
[contentEditable=true]
{
&:not([tabindex='-1'])
{
/* your SCSS for focusable elements goes here */
}
}
I've added it as an answer, because that was, what I was looking for, when Google redirected me to this Stackoverflow question.
EDIT: There is one more selector, which is focusable:
[contentEditable=true]
However, this is used very rarely.
$focusable:
'a[href]',
'area[href]',
'button',
'details',
'input',
'iframe',
'select',
'textarea',
// these are actually case sensitive but i'm not listing out all the possible variants
'[contentEditable=""]',
'[contentEditable="true"]',
'[contentEditable="TRUE"]',
'[tabindex]:not([tabindex^="-"])',
':not([disabled])';
I'm creating a SCSS list of all focusable elements and I thought this might help someone due to this question's Google rank.
A few things to note:
I changed :not([tabindex="-1"]) to :not([tabindex^="-"]) because it's perfectly plausible to generate -2 somehow. Better safe than sorry right?
Adding :not([tabindex^="-"]) to all the other focusable selectors is completely pointless. When using [tabindex]:not([tabindex^="-"]) it already includes all elements that you'd be negating with :not!
I included :not([disabled]) because disabled elements can never be focusable. So again it's useless to add it to every single element.
The ally.js accessibility library provides an unofficial, test-based list here:
https://allyjs.io/data-tables/focusable.html
(NB: Their page doesn't say how often tests were performed.)
Maybe this one can help:
function focus(el){
el.focus();
return el==document.activeElement;
}
return value: true = success, false = failed
Reff:
https://developer.mozilla.org/en-US/docs/Web/API/DocumentOrShadowRoot/activeElement
https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/focus
There is a much more elegant way to handle this:
Extend the element prototype like the sample below.
Then you can use it like:
element.isFocusable()
*Returns true if "element" is focusable and false if not.
/**
* Determining if an element can be focused on
* #return {Boolean}
*/
HTMLElement.prototype.isFocusable = function () {
var current = document.activeElement
if (current === this) return true
var protectEvent = (e) => e.stopImmediatePropagation()
this.addEventListener("focus", protectEvent, true)
this.addEventListener("blur", protectEvent, true)
this.focus({preventScroll:true})
var result = document.activeElement === this
this.blur()
if (current) current.focus({preventScroll:true})
this.removeEventListener("focus", protectEvent, true)
this.removeEventListener("blur", protectEvent, true)
return result
}
// A SIMPLE TEST
console.log(document.querySelector('a').isFocusable())
console.log(document.querySelector('a[href]').isFocusable())
<a>Not focusable</a>
Focusable