Change CSS class properties with jQuery

jquery css ajax class properties

214,674

Solution 1

You can't change CSS properties directly with jQuery. But you can achieve the same effect in at least two ways.

Dynamically Load CSS from a File

function updateStyleSheet(filename) {
    newstylesheet = "style_" + filename + ".css";

    if ($("#dynamic_css").length == 0) {
        $("head").append("<link>")
        css = $("head").children(":last");

        css.attr({
          id: "dynamic_css",
          rel:  "stylesheet",
          type: "text/css",
          href: newstylesheet
        });
    } else {
        $("#dynamic_css").attr("href",newstylesheet);
    }
}

The example above is copied from:

How To Switch CSS Files On-The-Fly Using jQuery

Dynamically Add a Style Element

$("head").append('<style type="text/css"></style>');
var newStyleElement = $("head").children(':last');
newStyleElement.html('.red{background:green;}');

The example code is copied from this JSFiddle fiddle originally referenced by Alvaro in their comment.

Solution 2

In case you cannot use different stylesheet by dynamically loading it, you can use this function to modify CSS class. Hope it helps you...

function changeCss(className, classValue) {
    // we need invisible container to store additional css definitions
    var cssMainContainer = $('#css-modifier-container');
    if (cssMainContainer.length == 0) {
        var cssMainContainer = $('<div id="css-modifier-container"></div>');
        cssMainContainer.hide();
        cssMainContainer.appendTo($('body'));
    }

    // and we need one div for each class
    classContainer = cssMainContainer.find('div[data-class="' + className + '"]');
    if (classContainer.length == 0) {
        classContainer = $('<div data-class="' + className + '"></div>');
        classContainer.appendTo(cssMainContainer);
    }

    // append additional style
    classContainer.html('<style>' + className + ' {' + classValue + '}</style>');
}

This function will take any class name and replace any previously set values with the new value. Note, you can add multiple values by passing the following into classValue: "background: blue; color:yellow".

Solution 3

Didn't find the answer I wanted, so I solved it myself:
modify a container div!

<div class="rotation"> <!-- Set the container div's css -->
  <div class="content" id='content-1'>This div gets scaled on hover</div>
</div>

<!-- Since there is no parent here the transform doesnt have specificity! -->
<div class="rotation content" id='content-2'>This div does not</div>

css you want to persist after executing $target.css()

.content:hover {
    transform: scale(1.5);
}

modify content's containing div with css()

$(".rotation").css("transform", "rotate(" + degrees + "deg)");

Codepen example

Solution 4

You can remove classes and add classes dynamically

$(document).ready(function(){
    $('#div').removeClass('left').addClass('right');
});

Solution 5

$(document)[0].styleSheets[styleSheetIndex].insertRule(rule, lineIndex);

styleSheetIndex is the index value that corresponds to which order you loaded the file in the <head> (e.g. 0 is the first file, 1 is the next, etc. if there is only one CSS file, use 0).

rule is a text string CSS rule. Like this: "body { display:none; }".

lineIndex is the line number in that file. To get the last line number, use $(document)[0].styleSheets[styleSheetIndex].cssRules.length. Just console.log that styleSheet object, it's got some interesting properties/methods.

Because CSS is a "cascade", whatever rule you're trying to insert for that selector you can just append to the bottom of the CSS file and it will overwrite anything that was styled at page load.

In some browsers, after manipulating the CSS file, you have to force CSS to "redraw" by calling some pointless method in DOM JS like document.offsetHeight (it's abstracted up as a DOM property, not method, so don't use "()") -- simply adding that after your CSSOM manipulation forces the page to redraw in older browsers.

So here's an example:

var stylesheet = $(document)[0].styleSheets[0]; stylesheet.insertRule('body { display:none; }', stylesheet.cssRules.length);

View more solutions

214,674

Alvaro

Front-end engineer

Updated on July 05, 2022

Comments

Alvaro almost 2 years
Is there a way to change the properties of a CSS class, not the element properties, using jQuery?

This is a practical example:

I have a div with class red
```
.red {background: red;}
```
I want to change class red background property, not elements that have class red background assigned.

If I do it with jQuery .css() method:
```
$('.red').css('background','green');
```
it will affect the elements that right now have class red. Up to here everything is fine. But if I make an Ajax call, and insert more divs with red class, those won't have a green background, they will have the initial red background.

I could call jQuery .css() method again. But I would like to know if there is a way to change the class itself. Please consider this is just a basic example.
- ayyp almost 12 years
  
  I don't believe you can change the actual classes with jQuery.
- Mr Griever almost 12 years
  
  I concur with Andrew Peacock, I know of no way to modify the actual css once loaded. However it seems trivial to perform update (changing the background from red to green) after changing an elements class.
- bobobobo over 7 years
  
  You may be able to manipulate the <style> element. See CSSStyleSheet.deleteRule and CSSStyleSheet.insertRule
- zontar almost 5 years
  
  Another use case, in fact the one that brought me here, is to resize a popup window (actually, a series of DIV) according to the viewport, without using JS but just by assigning a certain class and then changing the class definition.
Community over 10 years

That's quite smart actually! You should include the code into your answer and remove the link ;)
Doug S over 10 years

Yes, please include the actual code, instead of linking (which can break and make this answer useless).
Mathew Wolf about 10 years

Okay, sorry for linking :)
Tertium over 9 years

even shorter: $("head").append('<style id="style_changer" type="text/css"></style>'); and later in code: $('#style_changer').html('.red{background:green;}');
lindon fox about 9 years

As far as I can see, unlike this answer you are only appending and not replacing the values...
Kenny Evitt almost 9 years

There's nothing wrong with linking to the original source (and lots that's right) if you didn't write this code yourself.
kEnobus almost 8 years

Thanks! Excellent work. 2 tiny details from my IDE's syntax highlighter: 1. Remove var from var cssMainContainer = $('<div id="css-modifier-container"></div>'); 2. Add var to: classContainer = cssMainContainer.find('div[data-class="' + className + '"]');
Pierre-Antoine Guillaume over 6 years

Hi ! A tiny -1 because I don't see the point of using $(document)[0] in place of document.
Benny Schmidt over 6 years

@PierreAntoineGuillaume Hi. document is wrapped in the jQuery/$ object because the person who asked the question specified how to do it using jQuery. $(element) is not the same thing as element - jQuery converts the wrapped element to a set element that has access to jQuery's methods. $(element)[0] is equivalent to $(element).get(0). This is explained in further detail at learn.jquery.com/using-jquery-core/jquery-object Happy moderating...
Pierre-Antoine Guillaume over 6 years

I didn't know of that, that's interesting. I can't remove the minus one if you don't edit, which kinda sucks
Pierre-Antoine Guillaume over 6 years

"jQuery also has a method named .get() which provides a related function. Instead of returning a jQuery-wrapped DOM element, it returns the DOM element itself. Alternatively, because the jQuery object is "array-like," it supports array subscripting via brackets: either case, firstHeadingElem contains the native DOM element.", so there is indeed no point in doing $(document)[0].styleSheets[styleSheetIndex].insertRule(rule, lineIndex); over document.styleSheets[styleSheetIndex].insertRule(rule, lineIndex);
barrypicker over 6 years

How well does this perform on a very large DOM? It seems any jQuery selector will take a long time since it has to sift through the large DOM...
Akhil Gupta over 5 years

I'd like to add the I found this to be the easiest way to get a particular style sheet $(`link[href="style.css"]`).prop("sheet"); It will always return the exact style sheet you want to edit, as the href/url are, ideally, always unique within a webpage Edit: though it will only work if the style sheet is loaded using <link>
Akhil Gupta over 5 years

if using <style> assign it an id and use $("#myStyle").prop("sheet"); instead, same can be done with <link>
TroniPM over 4 years

This solution "Dynamically Add a Style Element" was perfect to me. Thank you! And @Tertium upgrade was even better.
JoePC about 3 years

One liner for the 2nd part: $("head").append('<style type="text/css">.red{background:green;}</style>'); Thanks, @Tertium