Set style using pure JavaScript [duplicate]

Question

I want to set body's background without jQuery.

Jquery code:

$('body').css('background','red');

Why the following code won't work in pure JavaScript?

document.getElementsByTagName('body').style['background']  = 'red';

Answer 1

document.getElementsByTagName('div')[0].style.backgroundColor = 'RED';

<div>sample</div>

Answer 2

There are many ways you can set the background color. But getElementsByTagName does not return a single object. It's a collection of objects

document.body.style.backgroundColor = "green"; // JavaScript

document.getElementsByTagName("body")[0].style.backgroundColor = "green"; // Another one

See the demo

Answer 3

getElementsByTagName does not return a single element, but instead a collection.

Try this:

document.getElementsByTagName('body')[0].style.backgroundColor  = 'red';