Remove all classes that begin with a certain string

user_5464 0
Viewed 112803

I have a div with id="a" that may have any number of classes attached to it, from several groups. Each group has a specific prefix. In the javascript, I don't know which class from the group is on the div. I want to be able to clear all classes with a given prefix and then add a new one. If I want to remove all of the classes that begin with "bg", how do I do that? Something like this, but that actually works:

$("#a").removeClass("bg*");
css jquery javascript
16 Answers

With jQuery, the actual DOM element is at index zero, this should work

$('#a')[0].className = $('#a')[0].className.replace(/\bbg.*?\b/g, '');
Pat_2380

You don't need any jQuery specific code to handle this. Just use a RegExp to replace them:

$("#a").className = $("#a").className.replace(/\bbg.*?\b/g, '');

You can modify this to support any prefix but the faster method is above as the RegExp will be compiled only once:

function removeClassByPrefix(el, prefix) {
    var regx = new RegExp('\\b' + prefix + '.*?\\b', 'g');
    el.className = el.className.replace(regx, '');
    return el;
}
Prestaul_56280

For modern browsers:

let element = $('#a')[0];
let cls = 'bg';

element.classList.remove.apply(element.classList, Array.from(element.classList).filter(v=>v.startsWith(cls)));
user_29443320
Admin1

Prestaul's answer was helpful, but it didn't quite work for me. The jQuery way to select an object by id didn't work. I had to use

document.getElementById("a").className

instead of

$("#a").className
user_54640

The top answer converted to jQuery for those wanting a jQuery only solution:

const prefix = 'prefix'
const classes = el.attr('class').split(' ').filter(c => !c.startsWith(prefix))
el.attr('class', classes.join(' ').trim())
user_12058710
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