getElementsByClassName returns code example

Example 1: getelementbyclass

var selector = document.getElementsByClassName('class-name');

Example 2: document getelementsbyclassname not getting all elements

//use this instead
document.querySelectorAll(".myclassname");

Example 3: get elment by id within get element byclassname

var targetDiv = document.getElementById("foo").getElementsByClassName("bar")[0];
targetDiv.textContent = "Goodbye world!";