I'm using a custom modernizer config which has selected the features I employ in my page (and only those features).
So, I'd like to simply grab the className of the <html> of the page so I can check to see how many no- prefixed classes are present (maybe checking classlist.match(/no-/g).length) and determine if my javascript should just give up.
It's not clear whether I should use
document.getElementsByTagName('html').className
or
$('html').attr('class')
or
document.documentElement.className
I will go for:
document.documentElement.className;
Because doesn't involve any function's call, neither an additional layer like jquery. Ideally this one is the cleanest and the fastest.
you can use jQuery hasClass` method:
Determine whether any of the matched elements are assigned the given class.
if ( $('html').hasClass('no-something')) {
// do something here
}
If using plain JS, the equivalent would be:
document.getElementsByTagName('html')[0].className
If you are using jquery in your project why to not use this one:
var classList = $("html").attr('class').split(/\s+/);
var prefix = 'no-';
$.each( classList, function(index, item){
if (item.substring(0, 2) === prefix) {
//do something
}
});
?
var allClasses = [];
var allElements = document.querySelectorAll('*');
for (var i = 0; i < allElements.length; i++) {
if (allElements[i].hasAttribute("class")) {
var classes = allElements[i].className.toString().split(/\s+/);
for (var j = 0; j < classes.length; j++) {
var cls = classes[j];
if (cls && allClasses.indexOf(cls) === -1)
allClasses.push(cls);
}
}
}
console.log(allClasses);
I'm adding emoticons to user input with:
function emoticons(html){
for(var emoticon in emotes){
for(var i = 0; i < emotes[emoticon].length; i++){
// Escape bad characters like )
var r = RegExp.escape(emotes[emoticon][i]);
// Set the regex up to replace all matches
r_escaped = new RegExp(r, "g");
// Replace the emote with the image
html = html.replace(r_escaped,"<img src=\""+icon_folder+"/face-"+emoticon+".png\" class=\"emoticonimg\" />");
}
}
return html;
}
The problem is sometimes the user input is in <code>xxx</code> blocks. Is there a way to get the emoticons function to ignore everything inside the code blocks if they exists. As they won't always exist?
Thanks
In order to do this easily, I'd work only with text nodes (not serialised HTML) and skip code elements.
You tagged it jquery, so there is some jQuery convenience code to ease cross browser issues with utility functions. It is very easily modified to work without jQuery, however.
var searchText = function(parentNode, regex, callback, skipElements) {
skipElements = skipElements || ['script', 'style'];
var node = parentNode.firstChild;
do {
if (node.nodeType == 1) {
var tag = node.tagName.toLowerCase();
if (~$.inArray(tag, skipElements)) {
continue;
}
searchText.call(this, node, regex, callback);
} else if (node.nodeType == 3) {
while (true) {
// Does this node have a match? If not, break and return.
if (!regex.test(node.data)) {
break;
}
node.data.replace(regex, function(match) {
var args = $.makeArray(arguments),
offset = args[args.length - 2],
newTextNode = node.splitText(offset);
callback.apply(window, [node].concat(args));
newTextNode.data = newTextNode.data.substr(match.length);
node = newTextNode;
});
}
}
} while (node = node.nextSibling);
};
searchText($('body')[0], /:\)/, function(node, match) {
var img = $('<img />')[0];
img.src = 'http://www.gravatar.com/avatar/80200e1488ab252197b7f0f51ae230ef?s=32&d=identicon&r=PG';
img.alt = match;
node.parentNode.insertBefore(img, node.nextSibling);
}, ['code']);
jsFiddle.
I wrote this function recently, it should do what you hope to achieve.
Using plain JavaScript (not jQuery), Is there any way to check if an element contains a class?
Currently, I'm doing this:
var test = document.getElementById("test");
var testClass = test.className;
switch (testClass) {
case "class1":
test.innerHTML = "I have class1";
break;
case "class2":
test.innerHTML = "I have class2";
break;
case "class3":
test.innerHTML = "I have class3";
break;
case "class4":
test.innerHTML = "I have class4";
break;
default:
test.innerHTML = "";
}
<div id="test" class="class1"></div>
The issue is that if I change the HTML to this...
<div id="test" class="class1 class5"></div>
...there's no longer an exact match, so I get the default output of nothing (""). But I still want the output to be I have class1 because the <div> still contains the .class1 class.
Use element.classList .contains method:
element.classList.contains(class);
This works on all current browsers and there are polyfills to support older browsers too.
Alternatively, if you work with older browsers and don't want to use polyfills to fix them, using indexOf is correct, but you have to tweak it a little:
function hasClass(element, className) {
return (' ' + element.className + ' ').indexOf(' ' + className+ ' ') > -1;
}
Otherwise you will also get true if the class you are looking for is part of another class name.
DEMO
jQuery uses a similar (if not the same) method.
Applied to the example:
As this does not work together with the switch statement, you could achieve the same effect with this code:
var test = document.getElementById("test"),
classes = ['class1', 'class2', 'class3', 'class4'];
test.innerHTML = "";
for(var i = 0, j = classes.length; i < j; i++) {
if(hasClass(test, classes[i])) {
test.innerHTML = "I have " + classes[i];
break;
}
}
It's also less redundant ;)
The easy and effective solution is trying .contains method.
test.classList.contains(testClass);
In modern browsers, you can just use the contains method of Element.classList :
testElement.classList.contains(className)
Demo
var testElement = document.getElementById('test');
console.log({
'main' : testElement.classList.contains('main'),
'cont' : testElement.classList.contains('cont'),
'content' : testElement.classList.contains('content'),
'main-cont' : testElement.classList.contains('main-cont'),
'main-content' : testElement.classList.contains('main-content'),
'main main-content' : testElement.classList.contains('main main-content')
});
<div id="test" class="main main-content content"></div>
Supported browsers
(from CanIUse.com)
Polyfill
If you want to use Element.classList but you also want to support older browsers, consider using this polyfill by Eli Grey.
Element.matches()
element.matches(selectorString)
According to MDN Web Docs:
The Element.matches() method returns true if the element would be selected by the specified selector string; otherwise, returns false.
Therefore, you can use Element.matches() to determine if an element contains a class.
const element = document.querySelector('#example');
console.log(element.matches('.foo')); // true
<div id="example" class="foo bar"></div>
View Browser Compatibility
This question is pretty solidly answered by element.classList.contains(), but people got pretty extravagant with their answers and made some bold claims, so I ran a benchmark.
Remember that each test is doing 1000 iterations, so most of these are still very fast. Unless you rely extensively on this for a specific operation, you won't see a performance difference.
I ran some tests with basically every way to do this. On my machine, (Win 10, 24gb, i7-8700), classList.contains performed super well. So did className.split(' ') which is effectively the same.
The winner though is classList.contains(). If you're not checking for classList to be undefined, ~(' ' + v.className + ' ').indexOf(' ' + classToFind + ' ') creeps ahead 5-15%
Since he wants to use switch(), I'm surprised no one has put this forth yet:
var test = document.getElementById("test");
var testClasses = test.className.split(" ");
test.innerHTML = "";
for(var i=0; i<testClasses.length; i++) {
switch(testClasses[i]) {
case "class1": test.innerHTML += "I have class1<br/>"; break;
case "class2": test.innerHTML += "I have class2<br/>"; break;
case "class3": test.innerHTML += "I have class3<br/>"; break;
case "class4": test.innerHTML += "I have class4<br/>"; break;
default: test.innerHTML += "(unknown class:" + testClasses[i] + ")<br/>";
}
}
Here is a little snippet If you’re trying to check wether element contains a class, without using jQuery.
function hasClass(element, className) {
return element.className && new RegExp("(^|\\s)" + className + "(\\s|$)").test(element.className);
}
This accounts for the fact that element might contain multiple class names separated by space.
OR
You can also assign this function to element prototype.
Element.prototype.hasClass = function(className) {
return this.className && new RegExp("(^|\\s)" + className + "(\\s|$)").test(this.className);
};
And trigger it like this (very similar to jQuery’s .hasClass() function):
document.getElementById('MyDiv').hasClass('active');
className is just a string so you can use the regular indexOf function to see if the list of classes contains another string.
This is a little old, but maybe someone will find my solution helpfull:
// Fix IE's indexOf Array
if (!Array.prototype.indexOf) {
Array.prototype.indexOf = function (searchElement) {
if (this == null) throw new TypeError();
var t = Object(this);
var len = t.length >>> 0;
if (len === 0) return -1;
var n = 0;
if (arguments.length > 0) {
n = Number(arguments[1]);
if (n != n) n = 0;
else if (n != 0 && n != Infinity && n != -Infinity) n = (n > 0 || -1) * Math.floor(Math.abs(n));
}
if (n >= len) return -1;
var k = n >= 0 ? n : Math.max(len - Math.abs(n), 0);
for (; k < len; k++) if (k in t && t[k] === searchElement) return k;
return -1;
}
}
// add hasClass support
if (!Element.prototype.hasClass) {
Element.prototype.hasClass = function (classname) {
if (this == null) throw new TypeError();
return this.className.split(' ').indexOf(classname) === -1 ? false : true;
}
}
A simplified oneliner:1
function hasClassName(classname,id) {
return String ( ( document.getElementById(id)||{} ) .className )
.split(/\s/)
.indexOf(classname) >= 0;
}
1 indexOf for arrays is not supported by IE (ofcourse). There are plenty of monkey patches to be found on the net for that.
I know there a lot of answers but most of these are for additional functions and additional classes. This is the one I personally use; much cleaner and much less lines of code!
if( document.body.className.match('category-page') ) {
console.log('yes');
}
I've created a prototype method which uses classList, if possible, else resorts to indexOf:
Element.prototype.hasClass = Element.prototype.hasClass ||
function(classArr){
var hasClass = 0,
className = this.getAttribute('class');
if( this == null || !classArr || !className ) return false;
if( !(classArr instanceof Array) )
classArr = classArr.split(' ');
for( var i in classArr )
// this.classList.contains(classArr[i]) // for modern browsers
if( className.split(classArr[i]).length > 1 )
hasClass++;
return hasClass == classArr.length;
};
///////////////////////////////
// TESTS (see browser's console when inspecting the output)
var elm1 = document.querySelector('p');
var elm2 = document.querySelector('b');
var elm3 = elm1.firstChild; // textNode
var elm4 = document.querySelector('text'); // SVG text
console.log( elm1, ' has class "a": ', elm1.hasClass('a') );
console.log( elm1, ' has class "b": ', elm1.hasClass('b') );
console.log( elm1, ' has class "c": ', elm1.hasClass('c') );
console.log( elm1, ' has class "d": ', elm1.hasClass('d') );
console.log( elm1, ' has class "a c": ', elm1.hasClass('a c') );
console.log( elm1, ' has class "a d": ', elm1.hasClass('a d') );
console.log( elm1, ' has class "": ', elm1.hasClass('') );
console.log( elm2, ' has class "a": ', elm2.hasClass('a') );
// console.log( elm3, ' has class "a": ', elm3.hasClass('a') );
console.log( elm4, ' has class "a": ', elm4.hasClass('a') );
<p class='a b c'>This is a <b>test</b> string</p>
<svg xmlns="http://www.w3.org/2000/svg" width="100px" height="50px">
<text x="10" y="20" class='a'>SVG Text Example</text>
</svg>
Test page
Here's a case-insensitive trivial solution:
function hasClass(element, classNameToTestFor) {
var classNames = element.className.split(' ');
for (var i = 0; i < classNames.length; i++) {
if (classNames[i].toLowerCase() == classNameToTestFor.toLowerCase()) {
return true;
}
}
return false;
}
Felix's trick of adding spaces to flank the className and the string you're searching for is the right approach to determining whether the elements has the class or not.
To have different behaviour according to the class, you may use function references, or functions, within a map:
function fn1(element){ /* code for element with class1 */ }
function fn2(element){ /* code for element with class2 */ }
function fn2(element){ /* code for element with class3 */ }
var fns={'class1': fn1, 'class2': fn2, 'class3': fn3};
for(var i in fns) {
if(hasClass(test, i)) {
fns[i](test);
}
}
for(var i in fns) iterates through the keys within the fns map.
Having no break after fnsi allows the code to be executed whenever there is a match - so that if the element has, f.i., class1 and class2, both fn1 and fn2 will be executed.
The advantage of this approach is that the code to execute for each class is arbitrary, like the one in the switch statement; in your example all the cases performed a similar operation, but tomorrow you may need to do different things for each.
You may simulate the default case by having a status variable telling whether a match was found in the loop or not.
If the element only has one class name you can quickly check it by getting the class attribute. The other answers are much more robust but this certainly has it's use cases.
if ( element.getAttribute('class') === 'classname' ) {
}
See this Codepen link for faster and easy way of checking an element if it has a specific class using vanilla JavaScript~!
hasClass (Vanilla JS)
function hasClass(element, cls) {
return (' ' + element.className + ' ').indexOf(' ' + cls + ' ') > -1;
}
This is supported on IE8+.
First we check if classList exists if it does we can use the contains method which is supported by IE10+. If we are on IE9 or 8 it falls back to using a regex, which is not as efficient but is a concise polyfill.
if (el.classList) {
el.classList.contains(className);
} else {
new RegExp('(^| )' + className + '( |$)', 'gi').test(el.className);
}
Alternatively if you are compiling with babel you can simply use:
el.classList.contains(className);
To check if an element contains a class, you use the contains() method of the classList property of the element:*
element.classList.contains(className);
*Suppose you have the following element:
<div class="secondary info">Item</div>*
To check if the element contains the secondary class, you use the following code:
const div = document.querySelector('div');
div.classList.contains('secondary'); // true
The following returns false because the element doesn’t have the class error:
const div = document.querySelector('div');
div.classList.contains('error'); // false
I think that perfect solution will be this
if ($(this).hasClass("your_Class"))
alert("positive");
else
alert("Negative");
I would Poly fill the classList functionality and use the new syntax. This way newer browser will use the new implementation (which is much faster) and only old browsers will take the performance hit from the code.
https://github.com/remy/polyfills/blob/master/classList.js
This is a bit off, but if you have an event that triggers switch, you can do without classes:
<div id="classOne1"></div>
<div id="classOne2"></div>
<div id="classTwo3"></div>
You can do
$('body').click( function() {
switch ( this.id.replace(/[0-9]/g, '') ) {
case 'classOne': this.innerHTML = "I have classOne"; break;
case 'classTwo': this.innerHTML = "I have classTwo"; break;
default: this.innerHTML = "";
}
});
.replace(/[0-9]/g, '') removes digits from id.
It is a bit hacky, but works for long switches without extra functions or loops
As the accepted answer suggests, Element.className returns a string, so you can easily check if a class exists by using the indexOf() method:
element.className.indexOf('animated') > -1
If you are interested in the performance difference between indexOf vs classList.contains, using indexOf seems to be slightly faster. I did a quick benchmark performance test to check that. Here are my findings: ClassName.indexOf vs ClassList.contains.
Try this one:
document.getElementsByClassName = function(cl) {
var retnode = [];
var myclass = new RegExp('\\b'+cl+'\\b');
var elem = this.getElementsByTagName('*');
for (var i = 0; i < elem.length; i++) {
var classes = elem[i].className;
if (myclass.test(classes)) retnode.push(elem[i]);
}
return retnode;
};
in which element is currently the class '.bar' ? Here is another solution but it's up to you.
var reg = /Image/g, // regexp for an image element
query = document.querySelector('.bar'); // returns [object HTMLImageElement]
query += this.toString(); // turns object into a string
if (query.match(reg)) { // checks if it matches
alert('the class .bar is attached to the following Element:\n' + query);
}
jsfiddle demo
Of course this is only a lookup for 1 simple element <img>(/Image/g) but you can put all in an array like <li> is /LI/g, <ul> = /UL/g etc.
Just to add to the answer for people trying to find class names within inline SVG elements.
Change the hasCLass() function to:
function hasClass(element, cls) {
return (' ' + element.getAttribute('class') + ' ').indexOf(' ' + cls + ' ') > -1;
}
Instead of using the className property you'll need to use the getAttribute() method to grab the class name.
I created these functions for my website, I use only vanilla javascript, maybe it will help someone.
First I created a function to get any HTML element:
//return an HTML element by ID, class or tag name
var getElement = function(selector) {
var elements = [];
if(selector[0] == '#') {
elements.push(document.getElementById(selector.substring(1, selector.length)));
} else if(selector[0] == '.') {
elements = document.getElementsByClassName(selector.substring(1, selector.length));
} else {
elements = document.getElementsByTagName(selector);
}
return elements;
}
Then the function that recieve the class to remove and the selector of the element:
var hasClass = function(selector, _class) {
var elements = getElement(selector);
var contains = false;
for (let index = 0; index < elements.length; index++) {
const curElement = elements[index];
if(curElement.classList.contains(_class)) {
contains = true;
break;
}
}
return contains;
}
Now you can use it like this:
hasClass('body', 'gray')
hasClass('#like', 'green')
hasClass('.button', 'active')
Hope it will help.
Tip: Try to remove dependencies of jQuery in your projects as much as you can - VanillaJS.
document.firstElementChild returns <html> tag then the classList attribute returns all classes added to it.
if(document.firstElementChild.classList.contains("your-class")){
// <html> has 'your-class'
} else {
// <html> doesn't have 'your-class'
}
Since .className is a string, you can use the string includes() method to check if your .className includes your class name:
element.className.includes("class1")
Using the classList is also ideal
HTML
<div id="box" class="myClass"></div>
JavaScript
const element = document.querySelector("#box");
element.classList.contains("myClass");
For me the most elegant and faster way to achieve it is:
function hasClass(el, cl) {
return el.classList ? el.classList.contains(cl) : !!el.className && !!el.className.match(new RegExp('(?: |^)' + cl + '(?: |$)'));
}
I'm trying to call object properties dynamically. I have solved the problem with eval() but i know that eval is evil and i want to do this on a better and safer way. My eval code:
// onfocus
var classes = this.getAttribute('class').split(' ');
for(var i = 0; i < classes.length; ++i) {
if(classes[i].match(/val\- */) !== null) {
var rule = classes[i].substr(4);
var instruction = eval('validate.instructionTexts.'+ rule +'()');
tooltip.appendChild( document.createTextNode(instruction) );
}
}
And I also have this code:
// onblur
var classes = this.getAttribute('class').split(' ');
for( var i = 0; i < classes.length; ++i ){
if(classes[i].match(/val\- */) !== null) {
var rule = classes[ i ].substr( 4 );
var tooltip = document.getElementsByClassName( 'tooltip' );
for( i = 0; i < tooltip.length; ++i){
tooltip[ i ].style.display = 'none';
}
eval('validate.rules.'+ rule +'(' + (this.value) + ')');
}
the problem with the second code is that I want to send a string to my property. this.value = the text i type in my textbox so i get correct string from this.value but i got this error.
if i type foo.
Uncaught ReferenceError: foo is not defined. Javascript thinks I trying to send a variabel but i want it to send a string. How can i solve this problems?
An HTML element's CSS class can be accessed directly from JS thru the className property.
JS object properties can be accessed via the dot-notation object.property or via the square-bracket-notation object['property'].
The regex /val\- */ matches the characters v, a, l, a '-' hyphen, and zero or more spaces, anywhere in the string.
The spaces are completely irrelevant since you're testing the result of a string that was split on spaces (and so it won't contain any spaces anymore).
Also, you're not anchoring the regex so a class of 'eval-test' will also be matched. I doubt that's what you're looking for.
If you were just testing for the classes starting with val-, then the indexOf method is much easier to read, and probably also a lot more efficient.
I've adjusted your bits of code accordingly. I'm assuming that the class names for your validation rules all start with val-, and that the rest of the class name is the name for the rule:
// onfocus
var classes = this.className.split(' ');
for(var i = 0; i < classes.length; ++i) {
if(classes[i].indexOf('val-') === 0) { // the class name starts with 'val-'
var rule = classes[i].substr(4);
var instruction = validate.instructionTexts[rule]();
tooltip.appendChild(document.createTextNode(instruction));
}
}
// onblur
var classes = this.className.split(' ');
for (var i = 0; i < classes.length; ++i ){
if(classes[i].indexOf('val-') === 0) { // the class name starts with 'val-'
var rule = classes[i].substr(4);
var tooltip = document.getElementsByClassName('tooltip');
for (i = 0; i < tooltip.length; ++i){
tooltip[i].style.display = 'none';
}
validate.rules[rule](this.value);
}
}
You do not need to use eval, you can access it as:
validate.rules[rule](this.value);
Which will solve your other problem too, which is that you are passing in the value of this.value which when eval()'d is not quoted as a string (which 'foo' is) so is being interpreted as a variable.
to get a property foo from object obj, you could use either
obj.foo
or
obj["foo"]
The first one won't allow reserved words or if the property contains spaces.
So your first example could change to
validate.instructionTexts[rule]()
I want to replace the contents within a html element so I'm using the following function for that:
function ReplaceContentInContainer(id,content) {
var container = document.getElementById(id);
container.innerHTML = content;
}
ReplaceContentInContainer('box','This is the replacement text');
<div id='box'></div>
The above works great but the problem is I have more than one html element on a page that I want to replace the contents of. So I can't use ids but classes instead. I have been told that javascript does not support any type of inbuilt get element by class function. So how can the above code be revised to make it work with classes instead of ids?
P.S. I don't want to use jQuery for this.
This code should work in all browsers.
function replaceContentInContainer(matchClass, content) {
var elems = document.getElementsByTagName('*'), i;
for (i in elems) {
if((' ' + elems[i].className + ' ').indexOf(' ' + matchClass + ' ')
> -1) {
elems[i].innerHTML = content;
}
}
}
The way it works is by looping through all of the elements in the document, and searching their class list for matchClass. If a match is found, the contents is replaced.
jsFiddle Example, using Vanilla JS (i.e. no framework)
Of course, all modern browsers now support the following simpler way:
var elements = document.getElementsByClassName('someClass');
but be warned it doesn't work with IE8 or before. See http://caniuse.com/getelementsbyclassname
Also, not all browsers will return a pure NodeList like they're supposed to.
You're probably still better off using your favorite cross-browser library.
document.querySelectorAll(".your_class_name_here");
That will work in "modern" browsers that implement that method (IE8+).
function ReplaceContentInContainer(selector, content) {
var nodeList = document.querySelectorAll(selector);
for (var i = 0, length = nodeList.length; i < length; i++) {
nodeList[i].innerHTML = content;
}
}
ReplaceContentInContainer(".theclass", "HELLO WORLD");
If you want to provide support for older browsers, you could load a stand-alone selector engine like Sizzle (4KB mini+gzip) or Peppy (10K mini) and fall back to it if the native querySelector method is not found.
Is it overkill to load a selector engine just so you can get elements with a certain class? Probably. However, the scripts aren't all that big and you will may find the selector engine useful in many other places in your script.
A Simple and an easy way
var cusid_ele = document.getElementsByClassName('custid');
for (var i = 0; i < cusid_ele.length; ++i) {
var item = cusid_ele[i];
item.innerHTML = 'this is value';
}
I'm surprised there are no answers using Regular Expressions. This is pretty much Andrew's answer, using RegExp.test instead of String.indexOf, since it seems to perform better for multiple operations, according to jsPerf tests.
It also seems to be supported on IE6.
function replaceContentInContainer(matchClass, content) {
var re = new RegExp("(?:^|\\s)" + matchClass + "(?!\\S)"),
elems = document.getElementsByTagName('*'), i;
for (i in elems) {
if (re.test(elems[i].className)) {
elems[i].innerHTML = content;
}
}
}
replaceContentInContainer("box", "This is the replacement text.");
If you look for the same class(es) frequently, you can further improve it by storing the (precompiled) regular expressions elsewhere, and passing them directly to the function, instead of a string.
function replaceContentInContainer(reClass, content) {
var elems = document.getElementsByTagName('*'), i;
for (i in elems) {
if (reClass.test(elems[i].className)) {
elems[i].innerHTML = content;
}
}
}
var reBox = /(?:^|\s)box(?!\S)/;
replaceContentInContainer(reBox, "This is the replacement text.");
This should work in pretty much any browser...
function getByClass (className, parent) {
parent || (parent=document);
var descendants=parent.getElementsByTagName('*'), i=-1, e, result=[];
while (e=descendants[++i]) {
((' '+(e['class']||e.className)+' ').indexOf(' '+className+' ') > -1) && result.push(e);
}
return result;
}
You should be able to use it like this:
function replaceInClass (className, content) {
var nodes = getByClass(className), i=-1, node;
while (node=nodes[++i]) node.innerHTML = content;
}
var elems = document.querySelectorAll('.one');
for (var i = 0; i < elems.length; i++) {
elems[i].innerHTML = 'content';
};
I assume this was not a valid option when this was originally asked, but you can now use document.getElementsByClassName('');. For example:
var elements = document.getElementsByClassName(names); // or:
var elements = rootElement.getElementsByClassName(names);
See the MDN documentation for more.
There are 3 different ways to get elements by class in javascript. But here for your query as you have multiple elements with the same class names you can use 2 methods:
getElementsByClassName Method - It returns all the elements with the specified class present in the document or within the parent element which called it.
function ReplaceContentInContainer(className, content) {
var containers = document.getElementsByClassName(className);
for (let i = 0; i < containers.length; i++) {
containers[i].innerHTML = content;
}
}
ReplaceContentInContainer('box', 'This is the replacement text');
<div class='box'></div>
querySelectorAll Method - It select element on the basic of CSS selectors. Pass your CSS class to it with a dot and it will return all the element having specified class as an array-like object.
function ReplaceContentInContainer(className, content) {
var containers = document.querySelectorAll(`.${className}`);
for (let i = 0; i < containers.length; i++) {
containers[i].innerHTML = content;
}
}
ReplaceContentInContainer('box', 'This is the replacement text');
<div class='box'></div>
I think something like:
function ReplaceContentInContainer(klass,content) {
var elems = document.getElementsByTagName('*');
for (i in elems){
if(elems[i].getAttribute('class') == klass || elems[i].getAttribute('className') == klass){
elems[i].innerHTML = content;
}
}
}
would work
jQuery handles this easy.
let element = $(.myclass);
element.html("Some string");
It changes all the .myclass elements to that text.
When some elements lack ID, I use jQuery like this:
$(document).ready(function()
{
$('.myclass').attr('id', 'myid');
});
This might be a strange solution, but maybe someone find it useful.