如何使用 DOM JavaScript 检测元素？

Question

I want to detect an element and change the backgroundColor through JavaScript but am having trouble with it.

I can't check for the element because it is a tag+class + tag+class...

Here's my code :

var one = document.getElementsByTagName("div");
var two = document.getElementsByClassName("red");
var three = document.getElementsByTagName("h2");
var four = document.getElementsByClassName("title");
one.two three.four.style.backgroundColor ="#00c497";

The format is "div.red h2.title".

How can I correctly detect an element using DOM JavaScript?

Answer 1

If you can, use querySelector for this:

 document.querySelector("div.red h2.title").style.backgroundColor = "#00c497";

 <div> <h2>Don't Touch</h2> </div> <div class="red"> <h2>Don't Touch</h2> <h2 class="title">Change</h2> </div>