Can javascript select object not displayed on DOM? - javascript

This is a really quick question :)
Just wondering here if its possible for javascript to select objects which aren't part of the DOM... like selecting an :after or :before content created by CSS?
for example...if I have a div and create a box through
div:after{
content: '.';
display: block;
width: 200px;
height: 200px;
background: green;
}
I still having difficulties to understand how those elements are created and since they can draw elements on screen but are not part of them DOM, does this mean it's not possible to interact with them?
Cheers

No, you won't be able to interact with them.
They're not part of the DOM, but rather are a manifestation of the style that was assigned.
If you need to add/remove the content, you can use class names.
<div id='myElem' class='withAfter'>some content</div>
div.withAfter:after{
content: '.';
display: block;
width: 200px;
height: 200px;
background: green;
}
Then add/remove the class as needed.

Check out the docs, I see that you cannot modify the properties directly, nor does it appear you can interact with the content created via pseudo-selectors. The best you can do is look at the properties: http://jsfiddle.net/uaN6z/
It looks something like this:
window.getComputedStyle(document.getElementById('test'), ':after')
The only viable way I've see to change it is to alter document style sheet. See this SO answer: Setting CSS pseudo-class rules from JavaScript
Good luck!

Related

How can I disable all CSS that can affect my widgets on another website?

I'm building JavaScript widgets that are supposed to be added onto other people's websites.
I style my widgets by dynamically adding a CSS to the pages they're on.
For example,
My CSS code below applies to a DIV inside my widget:
.myWidget { background-color: red; }
But a CSS file outside my own on a remote page might have:
div { border: 5px solid green; }
The CSS above would also apply to my widgets. How can I disable all other CSS outside my own?
Thanks
You could be Using shadow DOM
Shadow DOM MDN Web Docs
An important aspect of web components is encapsulation — being able to keep the markup structure, style, and behavior hidden and separate from other code on the page so that different parts do not clash, and the code can be kept nice and clean. The Shadow DOM API is a key part of this, providing a way to attach a hidden separated DOM to an element.
You can use the all shorthand property and the unset keyword to set each property's value to its initial value.
.myWidget {
all:unset;
background-color: red;
}
div {
background-color:yellow;
}
<div class="myWidget">Hello World!</div>

Prevent css interact in a div

I am doing a code that do some js injection of code in page, with JQuery. But in my input that i get in some pages modify it, I am putting all important attributes and define them as !important, but it's impossible to put all the attributes in all the tags.
Someone know how to disable all other css inside a div?
Solution I think:
I found a solution but i don't want to use it. Its eliminate al css from the page, while i am injecting the code after using that code I eliminate my css and code and apply the original code from the webpage
Thanks
If you're using that many !importants you're doing it wrong.
The solution to this problem is to properly organize your css. Important stuff last, because it overrides what was previously styled. Also use your selectors wisely. Example:
<a class="link">Link</a>
.
a:link { color: red; }
.
.
.
.link { color: green !important; } // Nop
a.link { color: green; } // Yup
If you override everything it will work with normal CSS rules on every page. Not what you were hoping for, but it is a solution.
css:
#myInsertDiv {
color: blue;
padding: 0;
margin: 0;
background: white;
border: 0px;
/* etc you have to restyle EVERY possible value */
}
html:
<div id="myInsertDiv"></div>
The main issue is you have to style every attribute, and reset everything else to a default value.
Or you can insert all the style information into the style attribute on the div, but that is probably doing it wrong too.
If I got you right you can use jQuery for modifying CSS properties on any elements of the page (huh), using something like this $('.Myclass').css('color','#ff0000')
And more about selectors in jQuery - http://api.jquery.com/category/selectors/

remove / reset inherited css from an element [duplicate]

This question already has answers here:
How to reset/remove CSS styles for a specific element or selector only
(17 answers)
Closed last month.
I know this question was asked before, but before marking it as a duplicate, I want to tell you that my situation is a little different from what I found on the internet.
I'm building and embedded script that people can put it on their sites. This script creates a div with a certain width/height and some information in it.
My problem is that some websites declare styles for div that are inherited by my div as well.
for example:
div{
background-color:red;
}
so if I don't set any background color to my div, it will show red even if I don't want that.
The only solutions I come along is to overwrite as many css proprieties, this way my div will show exactly as I want.
The problem with this solution is that there are too many css proprieties to overwrite and I want my script to be as light as it can be.
So my question is if you know another solution to my problem.
It can be in css/javascript /jQuery.
Thanks
"Resetting" styles for a specific element isn't possible, you'll have to overwrite all styles you don't want/need. If you do this with CSS directly or using JQuery to apply the styles (depends on what's easier for you, but I wouldn't recommend using JavaScript/JQuery for this, as it's completely unnecessary).
If your div is some kind of "widget" that can be included into other sites, you could try to wrap it into an iframe. This will "reset" the styles, because its content is another document, but maybe this affects how your widget works (or maybe breaks it completely) so this might not be possible in your case.
Only set the relevant / important CSS properties.
Example (only change the attributes which may cause your div to look completely different):
background: #FFF;
border: none;
color: #000;
display: block;
font: initial;
height: auto;
letter-spacing: normal;
line-height: normal;
margin: 0;
padding: 0;
text-transform: none;
visibility: visible;
width: auto;
word-spacing: normal;
z-index: auto;
Choose a very specific selector, such as div#donttouchme, <div id="donttouchme"></div>. Additionally, you can add `!important before every semicolon in the declaration. Your customers are deliberately trying to mess up your lay-out when this option fails.
You could try overwriting the CSS and use auto
I don't think this will work with color specifically, but I ran into an issue where i had a parent property such as
.parent {
left: 0px;
}
and then I was able to just define my child with something like
.child {
left: auto;
}
and it effectively "reset" the property.
Technically what you are looking for is the unset value in combination with the shorthand property all:
The unset CSS keyword resets a property to its inherited value if it inherits from its parent, and to its initial value if not. In other words, it behaves like the inherit keyword in the first case, and like the initial keyword in the second case. It can be applied to any CSS property, including the CSS shorthand all.
.customClass {
/* specific attribute */
color: unset;
}
.otherClass{
/* unset all attributes */
all: unset;
/* then set own attributes */
color: red;
}
You can use the initial value as well, this will default to the initial browser value.
.otherClass{
/* unset all attributes */
all: initial;
/* then set own attributes */
color: red;
}
As an alternative:
If possible it is probably good practice to encapsulate the class or id in a kind of namespace:
.namespace .customClass{
color: red;
}
<div class="namespace">
<div class="customClass"></div>
</div>
because of the specificity of the selector this will only influence your own classes
It is easier to accomplish this in "preprocessor scripting languages" like SASS with nesting capabilities:
.namespace{
.customClass{
color: red
}
}
Try this: Create a plain div without any style or content outside of the red div. Now you can use a loop over all styles of the plain div and assign then to your inner div to reset all styles.
Of course this doesn't work if someone assigns styles to all divs (i.e. without using a class. CSS would be div { ... }).
The usual solution for problems like this is to give your div a distinct class. That way, web designers of the sites can adjust the styling of your div to fit into the rest of the design.
As long as they are attributes like classes and ids you can remove them by javascript/jQuery class modifiers.
document.getElementById("MyElement").className = "";
There is no way to remove specific tag CSS other than overriding them (or using another element).
you may use this below option.
<style>
div:not(.no_common_style){
background-color:red;
}
</style>
now , if their any place where you do not want to apply default style you can use 'no_common_style' class as class.
ex:
<div class="no_common_style">
It will not display in red
</div>
From what I understand you want to use a div that inherits from no class but yours. As mentioned in the previous reply you cannot completely reset a div inheritance. However, what worked for me with that issue was to use another element - one that is not frequent and certainly not used in the current html page. A good example, is to use instead of then customize it to look just like your ideal would.
area { background-color : red; }
One simple approach would be to use the !important modifier in css, but this can be overridden in the same way from users.
Maybe a solution can be achieved with jquery by traversing the entire DOM to find your (re)defined classes and removing / forcing css styles.

Webkit scrollbar dynamic styling

I'm currently styling the scrollbar using Webkit's ::-webkit-scrollbar CSS properties and would like to change these properties on a mousemove event. The problem is that I can't seem to find a way to get to the scrollbar's CSS dynamically.
Is it possible to style the webkit scrollbar dynamically, through javascript (possibly using jQuery)?
There is a nice workaround for this problem, you can add multiple css classes with diffident styles for the scrollbar, and then change the classes dynamically with Javascript.
Example:
.red::-webkit-scrollbar { ... }
.blue::-webkit-scrollbar { ... }
A button that toggles between the classes red and blue:
$("#changecss").on("click", function(){
$(".red,.blue").toggleClass("red").toggleClass("blue");
});
Here is a working fiddle: http://jsfiddle.net/promatik/wZwJz/18/
Yes, you can do it.
You need to include dynamically css style rule into stylesheet.
And then to change it.
You can do it by this plugin
If you don't need to use jQuery - you can do it by pure Javascript:
link 1
link 2.
But there is cross-browser problems.
Also see Setting CSS pseudo-class rules from JavaScript
If you want to change a scrollbar properties when mouse is over it. You can do it with CSS, here an example http://jsfiddle.net/olgis/7Lg2R/ (sorry for ugly colorset).
If you want to change scrollbar colour if the mouse is over a container then look at this post Style webkit scrollbar on certain state . There are described several ways of doing it, with and without JavaScript.
REMARK: I do not know for which reason none of those example (with CSS neither JavaScript) do NOT work in my Firefox 11 for Mint, but all of them works perfectly in Chrome 18.0.1025.151.
i created page with four tabs each different color set as well as scroll bar
however this only worked by giving class to body tag
body.greenbody::-webkit-scrollbar {
width: 10px;
}
body.greenbody::-webkit-scrollbar-track {
background-color:rgb(0,50,0);
}
body.greenbody::-webkit-scrollbar-thumb {
background-image:url("../assets/ScrollGreen.png");
}
/
body.bluebody::-webkit-scrollbar {
width: 10px;
}
body.bluebody::-webkit-scrollbar-track {
background-color:rgb(0,0,50);
}
body.bluebody::-webkit-scrollbar-thumb {
background-image:url("../assets/ScrollBlue.png");
}
html
<body id="body" class="greenbody" bgcolor="#202020">
javascript for each tab button(only scroll bar section shown here)
document.getElementById("body").className="greenody";
.........other function()....
document.getElementById("body").className="bluebody";
ScreenShot1 GreenScrollBar Image
ScreenShot2 BlueScrollBar Image
For this you should replace the scrollbar altogether.
It's just a matter of picking whichever one gives you the easiest API.
You can style scrollbars with CSS3, these generally only work for internal scrollbars and not the actual browser main scrollbar. You can also add the MOZ attribute to the following.
::-webkit-scrollbar {
width: 10px;
height: 10px;
}
::-webkit-scrollbar-button:start:decrement,
::-webkit-scrollbar-button:end:increment {
display: none;
}
::-webkit-scrollbar-track-piece {
background-color: #3b3b3b;
-webkit-border-radius: 6px;
}
::-webkit-scrollbar-thumb:vertical {
-webkit-border-radius: 6px;
background: #666 url(scrollbar_thumb_bg.png) no-repeat center;
}
Demo: http://geryit.com/lib/custom-css3-scrollbars
Download Source: http://geryit.com/lib/custom-css3-scrollbars/custom-css3-scrollbars.zip
you can make a <style> tag with id="scrollbar_style" and then add css inside it dynamicly like this :
document.getElementById('scrollbar_style').innerHTML = '::-webkit-scrollbar{width:15px;}';
just remember that using innerHTML on an element WILL NOT JUST ADD your new code, it WILL ALSO DELETE whatever was inside that element.
problem solved.
you can define a function in JavaScript with your own css.
function overFlow(el) {
el.style.cssText = "overflow: auto;";
}
using in html:
<style>
::-webkit-scrollbar{display = none;}
</style>
<div id="overFlow" onclick="overFlow(this);">Something</div>
More Info: https://css-tricks.com/almanac/properties/s/scrollbar/

Auto fit CSS attribute to textarea

I am working on web application.
I wanted to apply auto height to textarea using CSS, dont want to use any script, jquery plugin and other stuff.
After applying class ( i.e. style property ) to textarea, it should automatically increase it's height not width as per content present it in.
In this case width should be fixed i.e. width: 98%; (In my case) only height needs to grow. So scroll bars should exist for text area.
I simply needed one CSS so that after applying to textarea, it should be auto grow like <DIV>.
Please folks do sugggest, is this possible using CSS. If this is not possible, then m okey if i get javascript statments to acheives my requirement.
Thanks,
Pravin
It's sort of semi-doable in html/CSS. There are, however, the usual caveats of browser support and, since it uses html5's contenteditable, it requires a fairly modern browser.
That said, the following works (in Chrome/Ubuntu 10.04):
<div id="wrap">
<div id="editThis" contenteditable>
</div>
</div>
With the following CSS:
div#editThis {
min-height: 4em;
height: auto;
width: 50%;
margin: 0 auto;
}
div#editThis:hover,
div#editThis:focus {
border: 1px solid #000;
}
Demo posted at jsbin
If you're only displaying text in a textarea and not using it to get more content input from the user then consider using a div and styling it to look like a textarea.
the other thing i have seen is an auto expanding textarea that grown in height as you type.
see here: http://james.padolsey.com/javascript/jquery-plugin-autoresize/
This is not possible with pure CSS, you will need to use JavaScript

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