How to get element by class name?
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?
Answer
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: