Can I use Javascript to change page styling? [duplicate]

Can I use Javascript to change page styling? [duplicate] - javascript

So far I have to do this:
elem.classList.add("first");
elem.classList.add("second");
elem.classList.add("third");
While this is doable in jQuery, like this
$(elem).addClass("first second third");
I'd like to know if there's any native way to add or remove.

elem.classList.add("first");
elem.classList.add("second");
elem.classList.add("third");
is equal
elem.classList.add("first","second","third");

The new spread operator makes it even easier to apply multiple CSS classes as array:
const list = ['first', 'second', 'third'];
element.classList.add(...list);

You can do like below
Add
elem.classList.add("first", "second", "third");
// OR
elem.classList.add(...["first","second","third"]);
Remove
elem.classList.remove("first", "second", "third");
// OR
elem.classList.remove(...["first","second","third"]);
Reference
TLDR;
In the straight forward case above removal should work. But in case of removal, you should make sure class exists before you remove them
const classes = ["first","second","third"];
classes.forEach(c => {
if (elem.classList.contains(c)) {
element.classList.remove(c);
}
})

The classList property ensures that duplicate classes are not unnecessarily added to the element. In order to keep this functionality, if you dislike the longhand versions or jQuery version, I'd suggest adding an addMany function and removeMany to DOMTokenList (the type of classList):
DOMTokenList.prototype.addMany = function(classes) {
var array = classes.split(' ');
for (var i = 0, length = array.length; i < length; i++) {
this.add(array[i]);
}
}
DOMTokenList.prototype.removeMany = function(classes) {
var array = classes.split(' ');
for (var i = 0, length = array.length; i < length; i++) {
this.remove(array[i]);
}
}
These would then be useable like so:
elem.classList.addMany("first second third");
elem.classList.removeMany("first third");
Update
As per your comments, if you wish to only write a custom method for these in the event they are not defined, try the following:
DOMTokenList.prototype.addMany = DOMTokenList.prototype.addMany || function(classes) {...}
DOMTokenList.prototype.removeMany = DOMTokenList.prototype.removeMany || function(classes) {...}

Since the add() method from the classList just allows to pass separate arguments and not a single array, you need to invoque add() using apply. For the first argument you will need to pass the classList reference from the same DOM node and as a second argument the array of classes that you want to add:
element.classList.add.apply(
element.classList,
['class-0', 'class-1', 'class-2']
);

Here is a work around for IE 10 and 11 users that seemed pretty straight forward.
var elem = document.getElementById('elem');
['first','second','third'].forEach(item => elem.classList.add(item));
<div id="elem">Hello World!</div>
Or
var elem = document.getElementById('elem'),
classes = ['first','second','third'];
classes.forEach(function(item) {
elem.classList.add(item);
});
<div id="elem">Hello World!</div>

To add class to a element
document.querySelector(elem).className+=' first second third';
UPDATE:
Remove a class
document.querySelector(elem).className=document.querySelector(elem).className.split(class_to_be_removed).join(" ");

Newer versions of the DOMTokenList spec allow for multiple arguments to add() and remove(), as well as a second argument to toggle() to force state.
At the time of writing, Chrome supports multiple arguments to add() and remove(), but none of the other browsers do. IE 10 and lower, Firefox 23 and lower, Chrome 23 and lower and other browsers do not support the second argument to toggle().
I wrote the following small polyfill to tide me over until support expands:
(function () {
/*global DOMTokenList */
var dummy = document.createElement('div'),
dtp = DOMTokenList.prototype,
toggle = dtp.toggle,
add = dtp.add,
rem = dtp.remove;
dummy.classList.add('class1', 'class2');
// Older versions of the HTMLElement.classList spec didn't allow multiple
// arguments, easy to test for
if (!dummy.classList.contains('class2')) {
dtp.add = function () {
Array.prototype.forEach.call(arguments, add.bind(this));
};
dtp.remove = function () {
Array.prototype.forEach.call(arguments, rem.bind(this));
};
}
// Older versions of the spec didn't have a forcedState argument for
// `toggle` either, test by checking the return value after forcing
if (!dummy.classList.toggle('class1', true)) {
dtp.toggle = function (cls, forcedState) {
if (forcedState === undefined)
return toggle.call(this, cls);
(forcedState ? add : rem).call(this, cls);
return !!forcedState;
};
}
})();
A modern browser with ES5 compliance and DOMTokenList are expected, but I'm using this polyfill in several specifically targeted environments, so it works great for me, but it might need tweaking for scripts that will run in legacy browser environments such as IE 8 and lower.

A very simple, non fancy, but working solution that I would have to believe is very cross browser:
Create this function
function removeAddClasses(classList,removeCollection,addCollection){
for (var i=0;i<removeCollection.length;i++){
classList.remove(removeCollection[i]);
}
for (var i=0;i<addCollection.length;i++){
classList.add(addCollection[i]);
}
}
Call it like this:
removeAddClasses(node.classList,arrayToRemove,arrayToAdd);
...where arrayToRemove is an array of class names to remove:
['myClass1','myClass2'] etcetera
...and arrayToAdd is an array of class names to add:
['myClass3','myClass4'] etcetera

The standard definiton allows only for adding or deleting a single class. A couple of small wrapper functions can do what you ask :
function addClasses (el, classes) {
classes = Array.prototype.slice.call (arguments, 1);
console.log (classes);
for (var i = classes.length; i--;) {
classes[i] = classes[i].trim ().split (/\s*,\s*|\s+/);
for (var j = classes[i].length; j--;)
el.classList.add (classes[i][j]);
}
}
function removeClasses (el, classes) {
classes = Array.prototype.slice.call (arguments, 1);
for (var i = classes.length; i--;) {
classes[i] = classes[i].trim ().split (/\s*,\s*|\s+/);
for (var j = classes[i].length; j--;)
el.classList.remove (classes[i][j]);
}
}
These wrappers allow you to specify the list of classes as separate arguments, as strings with space or comma separated items, or a combination. For an example see http://jsfiddle.net/jstoolsmith/eCqy7

Assume that you have an array of classes to being added, you can use ES6 spread syntax:
let classes = ['first', 'second', 'third'];
elem.classList.add(...classes);

A better way to add the multiple classes separated by spaces in a string is using the Spread_syntax with the split:
element.classList.add(...classesStr.split(" "));

I found a very simple method which is more modern and elegant way.
const el = document.querySelector('.m-element');
// To toggle
['class1', 'class2'].map((e) => el.classList.toggle(e));
// To add
['class1', 'class2'].map((e) => el.classList.add(e));
// To remove
['class1', 'class2'].map((e) => el.classList.remove(e));
Good thing is you can extend the class array or use any coming from API easily.

I liked #rich.kelly's answer, but I wanted to use the same nomenclature as classList.add() (comma seperated strings), so a slight deviation.
DOMTokenList.prototype.addMany = DOMTokenList.prototype.addMany || function() {
for (var i = 0; i < arguments.length; i++) {
this.add(arguments[i]);
}
}
DOMTokenList.prototype.removeMany = DOMTokenList.prototype.removeMany || function() {
for (var i = 0; i < arguments.length; i++) {
this.remove(arguments[i]);
}
}
So you can then use:
document.body.classList.addMany('class-one','class-two','class-three');
I need to test all browsers, but this worked for Chrome.
Should we be checking for something more specific than the existence of DOMTokenList.prototype.addMany? What exactly causes classList.add() to fail in IE11?

Another polyfill for element.classList is here. I found it via MDN.
I include that script and use element.classList.add("first","second","third") as it's intended.

One of the best solution is to check if an element exists and then proceed to add or possibly remove and above all if the element is empty, delete it.
/**
* #description detect if obj is an element
* #param {*} obj
* #returns {Boolean}
* #example
* see below
*/
function isElement(obj) {
if (typeof obj !== 'object') {
return false
}
let prototypeStr, prototype
do {
prototype = Object.getPrototypeOf(obj)
// to work in iframe
prototypeStr = Object.prototype.toString.call(prototype)
// '[object Document]' is used to detect document
if (
prototypeStr === '[object Element]' ||
prototypeStr === '[object Document]'
) {
return true
}
obj = prototype
// null is the terminal of object
} while (prototype !== null)
return false
}
/*
* Add multiple class
* addClasses(element,['class1','class2','class3'])
* el: element | document.querySelector(".mydiv");
* classes: passing:: array or string : [] | 'cl1,cl2' | 'cl1 cl2' | 'cl1|cl2'
*/
function addClasses(el, classes) {
classes = Array.prototype.slice.call(arguments, 1);
if ( isElement(el) ){ //if (document.body.contains(el)
for (var i = classes.length; i--;) {
classes[i] = Array.isArray(classes[i]) ? classes[i]: classes[i].trim().split(/\s*,\s*|\s+/);
for (var j = classes[i].length; j--;)
el.classList.add(classes[i][j]);
}
}
}
/*
* Remove multiple class
* Remove attribute class is empty
* addClasses(element,['class1','class2','class3'])
* el: element | document.querySelector(".mydiv");
* classes: passing:: array or string : [] | 'cl1,cl2' | 'cl1 cl2' | 'cl1|cl2'
*/
function removeClasses(el, classes) {
classes = Array.prototype.slice.call(arguments, 1);
if ( isElement(el) ) {
for (var i = classes.length; i--;) {
classes[i] = Array.isArray(classes[i]) ? classes[i]: classes[i].trim().split(/\s*,\s*|\s+/);
for (var j = classes[i].length; j--;)
el.classList.remove(classes[i][j]);
let cl = el.className.trim();
if (!cl){
el.removeAttribute('class');
}
}
}
}
var div = document.createElement("div");
div.id = 'test'; // div.setAttribute("id", "test");
div.textContent = 'The World';
//div.className = 'class';
// possible use: afterend, beforeend
document.body.insertAdjacentElement('beforeend', div);
// Everything written above you can do so:
//document.body.insertAdjacentHTML('beforeend', '<div id="text"></div>');
var el = document.querySelector("#test");
addClasses(el,'one,two,three,four');
removeClasses(el,'two,two,never,other');
el.innerHTML = 'I found: '+el.className;
// return : I found: four three one
#test {
display: inline-block;
border: 1px solid silver;
padding: 10px;
}

Related

Split a String Array and Store Values for each Iteration

So the variable classList stores all classes for the body. I then created a variable classListLength that has the length of classList so I can iterate through each index and then split each class. I do not know how to store the splits for each index as it loops through classList. Help me please.
var classList = jQuery('body').attr('class').split(' ');
var classListLength = classList.length;
var keyWords = function(array) {
for (var i = 0; i < classListLength; i++ ) {
classList[i].split('-');
}
}
if i do the following in the console
var keyWords = function(array) {
for (var i = 0; i < classListLength; i++ ) {
console.log(classList[i].split('-'));
}
}
I can see exactly what I want but I want to be able to store that and check it later on with a conditional.

var splitClassList = classList.map(function (class) {
return class.split('-');
});

So I solved what I needed. The below code allows me to iterate through my split classList. I then check the the specific class I want within the classList using .includes method and execute what I need done. If you guys know how to make this a bit more modular please chime in.
var brandClass
// Iterate though split classes
jQuery.each( classList, function(i) {
if ( classList[i].includes('product-wildridge') ) {
brandClass = classList[i];
}
});
// check specific class for certin keywords
var customTab = function(brandClass) {
if (brandClass.includes('wildridge') && brandClass.includes('deep') ) {
return true;
} else {
jQuery('#tab-fabric').css('display', 'none');
}
}
customTab(brandClass);

How to write Javascript to search nodes - without getElementsByClassName

I'm very new at recursion, and have been tasked with writing getElementsByClassName in JavaScript without libraries or the DOM API.
There are two matching classes, one of which is in the body tag itself, the other is in a p tag.
The code I wrote isn't working, and there must be a better way to do this. Your insight would be greatly appreciated.
var elemByClass = function(className) {
var result = [];
var nodes = document.body; //<body> is a node w/className, it needs to check itself.
var childNodes = document.body.childNodes; //then there's a <p> w/className
var goFetchClass = function(nodes) {
for (var i = 0; i <= nodes; i++) { // check the parent
if (nodes.classList == className) {
result.push(i);
console.log(result);
}
for (var j = 0; j <= childNodes; j++) { // check the children
if (childNodes.classList == className) {
result.push(j);
console.log(result);
}
goFetchClass(nodes); // recursion for childNodes
}
goFetchClass(nodes); // recursion for nodes (body)
}
return result;
};
};

There are some errors, mostly logical, in your code, here's what it should have looked like
var elemByClass = function(className) {
var result = [];
var pattern = new RegExp("(^|\\s)" + className + "(\\s|$)");
(function goFetchClass(nodes) {
for (var i = 0; i < nodes.length; i++) {
if ( pattern.test(nodes[i].className) ) {
result.push(nodes[i]);
}
goFetchClass(nodes[i].children);
}
})([document.body]);
return result;
};
Note the use of a regex instead of classList, as it makes no sense to use classList which is IE10+ to polyfill getElementsByClassName
Firstly, you'd start with the body, and check it's className property.
Then you'd get the children, not the childNodes as the latter includes text-nodes and comments, which can't have classes.
To recursively call the function, you'd pass the children in, and do the same with them, check for a class, get the children of the children, and call the function again, until there are no more children.

Here are some reasons:
goFetchClass needs an initial call after you've defined it - for example, you need a return goFetchClass(nodes) statement at the end of elemByClass function
the line for (var i = 0; i <= nodes; i++) { will not enter the for loop - did you mean i <= nodes.length ?
nodes.classList will return an array of classNames, so a direct equality such as nodes.classList == className will not work. A contains method is better.
Lastly, you may want to reconsider having 2 for loops for the parent and children. Why not have 1 for loop and then call goFetchClass on the children? such as, goFetchClass(nodes[i])?
Hope this helps.

Show/hide in javascript when no html access

I have this:
<div id="myid1">Text 1</div>
<div id="myid2">Text 2</div>
<div id="myid3">Text 3</div>
and I would hide all these elements by default. Then when I click on a link, I would like show all them at once. I looked for some solution in Javascript but it seem is not possible to declare multiple ID when using document.getElementById.
Precision: I seen many solution who suggest to use class instead ID. The problem is I work with an external application integrated in my site and I have access partially to html, but I can set javascript code inside a dedicated JS file.

You could create a function that retrieves several elements by their id, and simply iterate over that collection of elements to hide or show them:
function getElementsByIds(idArray) {
// initialise an array (over which we'll iterate, later)
var elements = [];
// if no arguments have been passed in, we quit here:
if (!arguments) {
return false;
}
else {
/* we're running a basic check to see if the first passed-argument
is an array; if it is, we use it: */
if (Object.prototype.toString.call(arguments[0]) === '[object Array]') {
idArray = idArray;
}
/* if a string has been passed-in (rather than an array), we
make an array of those strings: */
else if ('string' === typeof arguments[0]) {
idArray = [].slice.call(arguments);
}
// here we iterate over the array:
for (var i = 0, len = idArray.length; i < len; i++) {
// we test to see if we can retrieve an element by the id:
if (document.getElementById(idArray[i])) {
/* if we can, we add that found element to the array
we initialised earlier: */
elements.push(document.getElementById(idArray[i]));
}
}
}
// returning the elements:
return elements;
}
// here we toggle the display of the elements (between 'none' and 'block':
function toggle (elems) {
// iterating over each element in the passed-in array:
for (var i = 0, len = elems.length; i < len; i++) {
/* if the current display is (exactly) 'none', we change to 'block'
otherwise we change it to 'none': */
elems[i].style.display = elems[i].style.display === 'none' ? 'block' : 'none';
}
}
function hide (nodes) {
// iterating over the passed-in array of nodes
for (var i = 0, len = nodes.length; i < len; i++) {
// setting each of their display properties to 'none':
nodes[i].style.display = 'none';
}
}
// getting the elements:
var relevantElements = getElementsByIds('myid1','myid2','myid3'),
toggleButton = document.getElementById('buttonThatTogglesVisibilityId');
// binding the click-handling functionality of the button:
toggleButton.onclick = function(){
toggle (relevantElements);
};
// initially hiding the elements:
hide (relevantElements);
JS Fiddle demo.
References:
arguments keyword.
Array.prototype.push().
Array.protoype.slice().
document.getElementById().
Function.prototype.call().
Object.prototype.toString().
typeof.

Three options (at least):
1) Wrap them all in a parent container if this is an option. Then you can just target that, rather than the individual elements.
document.getElementById('#my_container').style.display = 'block';
2) Use a library like jQuery to target multiple IDs:
$('#myid1, #myid2, #myid3').show();
3) Use some ECMA5 magic, but it won't work in old browsers.
[].forEach.call(document.querySelectorAll('#myid1, #myid2, #myid3'), function(el) {
el.style.display = 'block'; //or whatever
});

If id="myid< increment-number >" then you can select these elements very easily.
Below code will select all elements that START WITH "myid".
$("div[id^='myid']").each(function (i, el) {
//do what ever you want here
}
See jquery doc
http://api.jquery.com/attribute-contains-selector/

Native Javascript Selections

I need to use native Javascript and for some of these I need to select more than one attribute (ex. a div with a class and id). Here is a code sample of what I've got so far. The example has all single selections.
var $ = function (selector) {
var elements = [];
var doc = document, i = doc.getElementsByTagName("div"),
iTwo = doc.getElementById("some_id"), // #some_id
iThree = doc.getElementsByTagName("input"),
// ^ Lets say I wanted to select an input with ID name as well. Should it not be doc.getElementsByTagName("input").getElementById("idname")
iFour = doc.getElementsByClassName("some_class"); // some_class
elements.push(i,iTwo,iThree,iFour);
return elements;
};
Oh yes, I forgot to mention I cannot use querySelector at all...

It depends on the properties you want to select on. For example, you might pass an object like:
{tagname: 'div', class: 'foo'};
and the function might be like:
function listToArray(x) {
for (var result=[], i=0, iLen=x.length; i<iLen; i++) {
result[i] = x[i];
}
return result;
}
function getByProperties(props) {
var el, elements;
var baseProps = {id:'id', tagName:'tagName'};
var result = [];
if ('tagName' in props) {
elements = listToArray(document.getElementsByTagName(props.tagName));
} else if ('id' in props) {
elements = [document.getElementById(props.id)];
}
for (var j=0, jLen=elements.length; j<jLen; j++) {
el = elements[j];
for (var prop in props) {
// Include all with tagName as used above. Avoids case sensitivity
if (prop == 'tagName' || (props.hasOwnProperty(prop) && props[prop] == el[prop])) {
result.push(el);
}
}
}
return result;
}
// e.g.
getByProperties({tagName:'div', className:'foo'});
However it's a simplistic approach, it won't do things like child or nth selectors.
You can perhaps look at someone else's selector function (there are a few around) and follow the fork to support non–qSA browsers. These are generally based on using a regular expression to tokenise a selector, then apply the selector manually similar to the above but more extensivly.
They also allow for case sensitivity for values (e.g. tagName value) and property names to some extent, as well as map HTML attribute names to DOM property names where required (e.g. class -> className, for -> htmlFor, etc.).

Get class list for element with jQuery

Is there a way in jQuery to loop through or assign to an array all of the classes that are assigned to an element?
ex.
<div class="Lorem ipsum dolor_spec sit amet">Hello World!</div>
I will be looking for a "special" class as in "dolor_spec" above. I know that I could use hasClass() but the actual class name may not necessarily be known at the time.

You can use document.getElementById('divId').className.split(/\s+/); to get you an array of class names.
Then you can iterate and find the one you want.
var classList = document.getElementById('divId').className.split(/\s+/);
for (var i = 0; i < classList.length; i++) {
if (classList[i] === 'someClass') {
//do something
}
}
jQuery does not really help you here...
var classList = $('#divId').attr('class').split(/\s+/);
$.each(classList, function(index, item) {
if (item === 'someClass') {
//do something
}
});

Why has no one simply listed.
$(element).attr("class").split(/\s+/);
EDIT: Split on /\s+/ instead of ' ' to fix #MarkAmery's objection. (Thanks #YashaOlatoto.)

On supporting browsers, you can use DOM elements' classList property.
$(element)[0].classList
It is an array-like object listing all of the classes the element has.
If you need to support old browser versions that don't support the classList property, the linked MDN page also includes a shim for it - although even the shim won't work on Internet Explorer versions below IE 8.

Here is a jQuery plugin which will return an array of all the classes the matched element(s) have
;!(function ($) {
$.fn.classes = function (callback) {
var classes = [];
$.each(this, function (i, v) {
var splitClassName = v.className.split(/\s+/);
for (var j = 0; j < splitClassName.length; j++) {
var className = splitClassName[j];
if (-1 === classes.indexOf(className)) {
classes.push(className);
}
}
});
if ('function' === typeof callback) {
for (var i in classes) {
callback(classes[i]);
}
}
return classes;
};
})(jQuery);
Use it like
$('div').classes();
In your case returns
["Lorem", "ipsum", "dolor_spec", "sit", "amet"]
You can also pass a function to the method to be called on each class
$('div').classes(
function(c) {
// do something with each class
}
);
Here is a jsFiddle I set up to demonstrate and test http://jsfiddle.net/GD8Qn/8/
Minified Javascript
;!function(e){e.fn.classes=function(t){var n=[];e.each(this,function(e,t){var r=t.className.split(/\s+/);for(var i in r){var s=r[i];if(-1===n.indexOf(s)){n.push(s)}}});if("function"===typeof t){for(var r in n){t(n[r])}}return n}}(jQuery);

You should try this one:
$("selector").prop("classList")
It returns a list of all current classes of the element.

var classList = $(element).attr('class').split(/\s+/);
$(classList).each(function(index){
//do something
});

$('div').attr('class').split(' ').each(function(cls){ console.log(cls);})

Update:
As #Ryan Leonard pointed out correctly, my answer doesn't really fix the point I made my self... You need to both trim and remove double spaces with (for example) string.replace(/ +/g, " ").. Or you could split the el.className and then remove empty values with (for example) arr.filter(Boolean).
const classes = element.className.split(' ').filter(Boolean);
or more modern
const classes = element.classList;
Old:
With all the given answers, you should never forget to user .trim() (or $.trim())
Because classes gets added and removed, it can happen that there are multiple spaces between class string.. e.g. 'class1 class2 class3'..
This would turn into ['class1', 'class2','','','', 'class3']..
When you use trim, all multiple spaces get removed..

Might this can help you too. I have used this function to get classes of childern element..
function getClickClicked(){
var clickedElement=null;
var classes = null;<--- this is array
ELEMENT.on("click",function(e){//<-- where element can div,p span, or any id also a class
clickedElement = $(e.target);
classes = clickedElement.attr("class").split(" ");
for(var i = 0; i<classes.length;i++){
console.log(classes[i]);
}
e.preventDefault();
});
}
In your case you want doler_ipsum class u can do like this now calsses[2];.

Thanks for this - I was having a similar issue, as I'm trying to programatically relate objects will hierarchical class names, even though those names might not necessarily be known to my script.
In my script, I want an <a> tag to turn help text on/off by giving the <a> tag [some_class] plus the class of toggle, and then giving it's help text the class of [some_class]_toggle. This code is successfully finding the related elements using jQuery:
$("a.toggle").toggle(function(){toggleHelp($(this), false);}, function(){toggleHelp($(this), true);});
function toggleHelp(obj, mode){
var classList = obj.attr('class').split(/\s+/);
$.each( classList, function(index, item){
if (item.indexOf("_toggle") > 0) {
var targetClass = "." + item.replace("_toggle", "");
if(mode===false){$(targetClass).removeClass("off");}
else{$(targetClass).addClass("off");}
}
});
}

Try This. This will get you the names of all the classes from all the elements of document.
$(document).ready(function() {
var currentHtml="";
$('*').each(function() {
if ($(this).hasClass('') === false) {
var class_name = $(this).attr('class');
if (class_name.match(/\s/g)){
var newClasses= class_name.split(' ');
for (var i = 0; i <= newClasses.length - 1; i++) {
if (currentHtml.indexOf(newClasses[i]) <0) {
currentHtml += "."+newClasses[i]+"<br>{<br><br>}<br>"
}
}
}
else
{
if (currentHtml.indexOf(class_name) <0) {
currentHtml += "."+class_name+"<br>{<br><br>}<br>"
}
}
}
else
{
console.log("none");
}
});
$("#Test").html(currentHtml);
});
Here is the working example: https://jsfiddle.net/raju_sumit/2xu1ujoy/3/

For getting the list of classes applied to element we can use
$('#elementID').prop('classList')
For adding or removing any classes we can follow as below.
$('#elementID').prop('classList').add('yourClassName')
$('#elementID').prop('classList').remove('yourClassName')
And for simply checking if the class is present or not we can use hasClass

I had a similar issue, for an element of type image. I needed to check whether the element was of a certain class. First I tried with:
$('<img>').hasClass("nameOfMyClass");
but I got a nice "this function is not available for this element".
Then I inspected my element on the DOM explorer and I saw a very nice attribute that I could use: className. It contained the names of all the classes of my element separated by blank spaces.
$('img').className // it contains "class1 class2 class3"
Once you get this, just split the string as usual.
In my case this worked:
var listOfClassesOfMyElement= $('img').className.split(" ");
I am assuming this would work with other kinds of elements (besides img).
Hope it helps.

javascript provides a classList attribute for a node element in dom. Simply using
element.classList
will return a object of form
DOMTokenList {0: "class1", 1: "class2", 2: "class3", length: 3, item: function, contains: function, add: function, remove: function…}
The object has functions like contains, add, remove which you can use

A bit late, but using the extend() function lets you call "hasClass()" on any element, e.g.:
var hasClass = $('#divId').hasClass('someClass');
(function($) {
$.extend({
hasClass: new function(className) {
var classAttr = $J(this).attr('class');
if (classAttr != null && classAttr != undefined) {
var classList = classAttr.split(/\s+/);
for(var ix = 0, len = classList.length;ix < len;ix++) {
if (className === classList[ix]) {
return true;
}
}
}
return false;
}
}); })(jQuery);

The question is what Jquery is designed to do.
$('.dolor_spec').each(function(){ //do stuff
And why has no one given .find() as an answer?
$('div').find('.dolor_spec').each(function(){
..
});
There is also classList for non-IE browsers:
if element.classList.contains("dolor_spec") { //do stuff

Develop Reference

JavaScript is the programming language of the Web.

Can I use Javascript to change page styling? [duplicate] - javascript

So far I have to do this: elem.classList.add("first"); elem.classList.add("second"); elem.classList.add("third"); While this is doable in jQuery, like this $(elem).addClass("first second third"); I'd like to know if there's any native way to add or remove.

elem.classList.add("first"); elem.classList.add("second"); elem.classList.add("third"); is equal elem.classList.add("first","second","third");

The new spread operator makes it even easier to apply multiple CSS classes as array: const list = ['first', 'second', 'third']; element.classList.add(...list);

To add class to a element document.querySelector(elem).className+=' first second third'; UPDATE: Remove a class document.querySelector(elem).className=document.querySelector(elem).className.split(class_to_be_removed).join(" ");

Assume that you have an array of classes to being added, you can use ES6 spread syntax: let classes = ['first', 'second', 'third']; elem.classList.add(...classes);

A better way to add the multiple classes separated by spaces in a string is using the Spread_syntax with the split: element.classList.add(...classesStr.split(" "));

Another polyfill for element.classList is here. I found it via MDN. I include that script and use element.classList.add("first","second","third") as it's intended.

Related

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How to write Javascript to search nodes - without getElementsByClassName

Show/hide in javascript when no html access

Native Javascript Selections

Get class list for element with jQuery

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