How to get element by class name?
JavascriptDomJavascript Problem Overview
Using JavaScript, we can get element by id using following syntax:
var x=document.getElementById("by_id");
I tried following to get element by class:
var y=document.getElementByClass("by_class");
But it resulted into error:
getElementByClass is not function
How can I get an element by its class?
Javascript Solutions
Solution 1 - Javascript
The name of the DOM function is actually getElementsByClassName, not getElementByClassName, simply because more than one element on the page can have the same class, hence: Elements.
The return value of this will be a NodeList instance, or a superset of the NodeList (FF, for instance returns an instance of HTMLCollection). At any rate: the return value is an array-like object:
var y = document.getElementsByClassName('foo');
var aNode = y[0];
If, for some reason you need the return object as an array, you can do that easily, because of its magic length property:
var arrFromList = Array.prototype.slice.call(y);
//or as per AntonB's comment:
var arrFromList = [].slice.call(y);
As yckart suggested querySelector('.foo') and querySelectorAll('.foo') would be preferable, though, as they are, indeed, better supported (93.99% vs 87.24%), according to caniuse.com:
Solution 2 - Javascript
Another option is to use querySelector('.foo') or querySelectorAll('.foo') which have broader browser support than getElementsByClassName.
Solution 3 - Javascript
You need to use the document.getElementsByClassName('class_name');
and dont forget that the returned value is an array of elements so if you want the first one use:
document.getElementsByClassName('class_name')[0]
UPDATE
Now you can use:
document.querySelector(".class_name") to get the first element with the class_name CSS class (null will be returned if non of the elements on the page has this class name)
or document.querySelectorAll(".class_name") to get a NodeList of elements with the class_name css class (empty NodeList will be returned if non of. the elements on the the page has this class name).
Solution 4 - Javascript
you can use
getElementsByClassName
suppose you have some elements and applied a class name 'test', so, you can get elements like as following
var tests = document.getElementsByClassName('test');
its returns an instance NodeList, or its superset: HTMLCollection (FF).