Toggle classname onclick JavaScript

问题:

I am nearly there, just a little unsure as to my code setup, I basically want to remove a class on click, and add it back again onclick, then remove onclick, then add onclick. And so on! Here's what I have, it's nearly there, but if there is a nicer way to do this then please help! Thank you.

document.getElementById('myButton').onclick = function() {
    myButton.className = myButton.className.replace(/(?:^|\s)active(?!\S)/g, '') ? 'active': jbar.className.replace(/(?:^|\s)active(?!\S)/g, '') ;
}

Any help much appreciated!

回答1:

If you want to use a ternary operator, use this:

document.getElementById('myButton').onclick = function() {

    var className = ' ' + myButton.className + ' ';

    this.className = ~className.indexOf(' active ') ?
                         className.replace(' active ', ' ') :
                         this.className + ' active';
}

---

For clarity, I'd use a regular if/else:

document.getElementById('myButton').onclick = function() {

    var className = ' ' + myButton.className + ' ';

    if ( ~className.indexOf(' active ') ) {
        this.className = className.replace(' active ', ' ');
    } else {
        this.className += ' active';
    }              
}

Here's the fiddle: http://jsfiddle.net/ttEGY/

回答2:

I am really surprised nobody mentioned classList here. So just to be complete: Alternative solution would be to use classList method toggle().

Your case would then simply be:

document.getElementById('myButton').onclick = function() {
    this.classList.toggle('active');
}

e.classList.toggle() has good support (except for, ehm, IE, It's there since IE10). Click here for complete browser compatibility.

回答3:

If JQuery is okay for you it really is as simple as

$(myButton).toggleClass('active')

http://jsfiddle.net/bikeshedder/eRJB4/

回答4:

Suggest common realization of toggleClass method:

function toggleClass(element, tClass) {
    tClass = tClass.replace(/\s/g, "");

    var classes =  element.className;
    element.className = classes.indexOf(tClass) !== -1 
        ? classes.replace(" " + tClass, "")
        : classes + " " + tClass;
}

using:

var element = document.getElementById('myId');
toggleClass(element, 'active');

回答5:

Implementation using Array methods:

const toggleClass = (element, className) => {
  let classNames = element.className.split(' ');
  let index = classNames.indexOf(className);
  if (index === -1) {
    classNames.push(className);
  } else {
    classNames.splice(index, 1);
  }
  element.className = classNames.filter(item => item !== '').join(' ');
}

Usage:

let body = document.getElementsByTagName('body')[0];
toggleClass(body, 'ready');

Plunker