How to add/remove a class in JavaScript?
Since element.classList
is not supported in IE 9 and Safari-5, what's an alternative cross-browser solution?
No-frameworks please.
Solution must work in at least IE 9, S开发者_运维知识库afari 5, FireFox 4, Opera 11.5, and Chrome.
Related posts (but does not contain solution):
how to add and remove css class
Add and remove a class with animation
Add remove class?
Here is solution for addClass, removeClass, hasClass in pure javascript solution.
Actually it's from http://jaketrent.com/post/addremove-classes-raw-javascript/
function hasClass(ele,cls) {
return !!ele.className.match(new RegExp('(\\s|^)'+cls+'(\\s|$)'));
}
function addClass(ele,cls) {
if (!hasClass(ele,cls)) ele.className += " "+cls;
}
function removeClass(ele,cls) {
if (hasClass(ele,cls)) {
var reg = new RegExp('(\\s|^)'+cls+'(\\s|$)');
ele.className=ele.className.replace(reg,' ');
}
}
Look at these oneliners:
Remove class:
element.classList.remove('hidden');
Add class (will not add it twice if already present):
element.classList.add('hidden');
Toggle class (adds the class if it's not already present and removes it if it is)
element.classList.toggle('hidden');
That's all! I made a test - 10000 iterations. 0.8s.
I just wrote these up:
function addClass(el, classNameToAdd){
el.className += ' ' + classNameToAdd;
}
function removeClass(el, classNameToRemove){
var elClass = ' ' + el.className + ' ';
while(elClass.indexOf(' ' + classNameToRemove + ' ') !== -1){
elClass = elClass.replace(' ' + classNameToRemove + ' ', '');
}
el.className = elClass;
}
I think they'll work in all browsers.
The simplest is element.classList
which has remove(name)
, add(name)
, toggle(name)
, and contains(name)
methods and is now supported by all major browsers.
For older browsers you change element.className
. Here are two helper:
function addClass(element, className){
element.className += ' ' + className;
}
function removeClass(element, className) {
element.className = element.className.replace(
new RegExp('( |^)' + className + '( |$)', 'g'), ' ').trim();
}
One way to play around with classes without frameworks/libraries would be using the property Element.className, which "gets and sets the value of the class attribute of the specified element." (from the MDN documentation).
As @matías-fidemraizer already mentioned in his answer, once you get the string of classes for your element you can use any methods associated with strings to modify it.
Here's an example:
Assuming you have a div with the ID "myDiv" and that you want to add to it the class "main__section" when the user clicks on it,
window.onload = init;
function init() {
document.getElementById("myDiv").onclick = addMyClass;
}
function addMyClass() {
var classString = this.className; // returns the string of all the classes for myDiv
var newClass = classString.concat(" main__section"); // Adds the class "main__section" to the string (notice the leading space)
this.className = newClass; // sets className to the new string
}
Read this Mozilla Developer Network article:
- https://developer.mozilla.org/en/DOM/element.className
Since element.className property is of type string, you can use regular String object functions found in any JavaScript implementation:
If you want to add a class, first use
String.indexOf
in order to check if class is present in className. If it's not present, just concatenate a blank character and the new class name to this property. If it's present, do nothing.If you want to remove a class, just use
String.replace
, replacing "[className]" with an empty string. Finally useString.trim
to remove blank characters at the start and end ofelement.className
.
Fixed the solution from @Paulpro
- Do not use "class", as it is a reserved word
removeClass
function was broken, as it bugged out after repeated use.
`
function addClass(el, newClassName){
el.className += ' ' + newClassName;
}
function removeClass(el, removeClassName){
var elClass = el.className;
while(elClass.indexOf(removeClassName) != -1) {
elClass = elClass.replace(removeClassName, '');
elClass = elClass.trim();
}
el.className = elClass;
}
The solution is to
Shim .classList
:
Either use the DOM-shim or use Eli Grey's shim below
Disclaimer: I believe the support is FF3.6+, Opera10+, FF5, Chrome, IE8+
/*
* classList.js: Cross-browser full element.classList implementation.
* 2011-06-15
*
* By Eli Grey, http://eligrey.com
* Public Domain.
* NO WARRANTY EXPRESSED OR IMPLIED. USE AT YOUR OWN RISK.
*/
/*global self, document, DOMException */
/*! @source http://purl.eligrey.com/github/classList.js/blob/master/classList.js*/
if (typeof document !== "undefined" && !("classList" in document.createElement("a"))) {
(function (view) {
"use strict";
var
classListProp = "classList"
, protoProp = "prototype"
, elemCtrProto = (view.HTMLElement || view.Element)[protoProp]
, objCtr = Object
, strTrim = String[protoProp].trim || function () {
return this.replace(/^\s+|\s+$/g, "");
}
, arrIndexOf = Array[protoProp].indexOf || function (item) {
var
i = 0
, len = this.length
;
for (; i < len; i++) {
if (i in this && this[i] === item) {
return i;
}
}
return -1;
}
// Vendors: please allow content code to instantiate DOMExceptions
, DOMEx = function (type, message) {
this.name = type;
this.code = DOMException[type];
this.message = message;
}
, checkTokenAndGetIndex = function (classList, token) {
if (token === "") {
throw new DOMEx(
"SYNTAX_ERR"
, "An invalid or illegal string was specified"
);
}
if (/\s/.test(token)) {
throw new DOMEx(
"INVALID_CHARACTER_ERR"
, "String contains an invalid character"
);
}
return arrIndexOf.call(classList, token);
}
, ClassList = function (elem) {
var
trimmedClasses = strTrim.call(elem.className)
, classes = trimmedClasses ? trimmedClasses.split(/\s+/) : []
, i = 0
, len = classes.length
;
for (; i < len; i++) {
this.push(classes[i]);
}
this._updateClassName = function () {
elem.className = this.toString();
};
}
, classListProto = ClassList[protoProp] = []
, classListGetter = function () {
return new ClassList(this);
}
;
// Most DOMException implementations don't allow calling DOMException's toString()
// on non-DOMExceptions. Error's toString() is sufficient here.
DOMEx[protoProp] = Error[protoProp];
classListProto.item = function (i) {
return this[i] || null;
};
classListProto.contains = function (token) {
token += "";
return checkTokenAndGetIndex(this, token) !== -1;
};
classListProto.add = function (token) {
token += "";
if (checkTokenAndGetIndex(this, token) === -1) {
this.push(token);
this._updateClassName();
}
};
classListProto.remove = function (token) {
token += "";
var index = checkTokenAndGetIndex(this, token);
if (index !== -1) {
this.splice(index, 1);
this._updateClassName();
}
};
classListProto.toggle = function (token) {
token += "";
if (checkTokenAndGetIndex(this, token) === -1) {
this.add(token);
} else {
this.remove(token);
}
};
classListProto.toString = function () {
return this.join(" ");
};
if (objCtr.defineProperty) {
var classListPropDesc = {
get: classListGetter
, enumerable: true
, configurable: true
};
try {
objCtr.defineProperty(elemCtrProto, classListProp, classListPropDesc);
} catch (ex) { // IE 8 doesn't support enumerable:true
if (ex.number === -0x7FF5EC54) {
classListPropDesc.enumerable = false;
objCtr.defineProperty(elemCtrProto, classListProp, classListPropDesc);
}
}
} else if (objCtr[protoProp].__defineGetter__) {
elemCtrProto.__defineGetter__(classListProp, classListGetter);
}
}(self));
}
Improved version of emil's code (with trim())
function hasClass(ele,cls) {
return !!ele.className.match(new RegExp('(\\s|^)'+cls+'(\\s|$)'));
}
function addClass(ele,cls) {
if (!hasClass(ele,cls)) ele.className = ele.className.trim() + " " + cls;
}
function removeClass(ele,cls) {
if (hasClass(ele,cls)) {
var reg = new RegExp('(\\s|^)'+cls+'(\\s|$)');
ele.className = ele.className.replace(reg,' ');
ele.className = ele.className.trim();
}
}
function addClass(element, classString) {
element.className = element
.className
.split(' ')
.filter(function (name) { return name !== classString; })
.concat(classString)
.join(' ');
}
function removeClass(element, classString) {
element.className = element
.className
.split(' ')
.filter(function (name) { return name !== classString; })
.join(' ');
}
Just in case if anyone would like to have prototype functions built for elements, this is what I use when I need to manipulate classes of different objects:
Element.prototype.addClass = function (classToAdd) {
var classes = this.className.split(' ')
if (classes.indexOf(classToAdd) === -1) classes.push(classToAdd)
this.className = classes.join(' ')
}
Element.prototype.removeClass = function (classToRemove) {
var classes = this.className.split(' ')
var idx =classes.indexOf(classToRemove)
if (idx !== -1) classes.splice(idx,1)
this.className = classes.join(' ')
}
Use them like:
document.body.addClass('whatever')
or document.body.removeClass('whatever')
Instead of body you can also use any other element (div, span, you name it)
add css classes: cssClassesStr += cssClassName;
remove css classes: cssClassStr = cssClassStr.replace(cssClassName,"");
add attribute 'Classes': object.setAttribute("class", ""); //pure addition of this attribute
remove attribute: object.removeAttribute("class");
A easy to understand way:
// Add class
DOMElement.className += " one";
// Example:
// var el = document.body;
// el.className += " two"
// Remove class
function removeDOMClass(element, className) {
var oldClasses = element.className,
oldClassesArray = oldClasses.split(" "),
newClassesArray = [],
newClasses;
// Sort
var currentClassChecked,
i;
for ( i = 0; i < oldClassesArray.length; i++ ) {
// Specified class will not be added in the new array
currentClassChecked = oldClassesArray[i];
if( currentClassChecked !== className ) {
newClassesArray.push(currentClassChecked);
}
}
// Order
newClasses = newClassesArray.join(" ");
// Apply
element.className = newClasses;
return element;
}
// Example:
// var el = document.body;
// removeDOMClass(el, "two")
https://gist.github.com/sorcamarian/ff8db48c4dbf4f5000982072611955a2
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