Answers for "how to use getelementsbyclassname"

javascript get element by class

var elementsArray = document.getElementsByClassName("someclassname");

getelementbyclass

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

javascript document object model getElementsByClassName

document.getElementsByClassName('test')

get elment by id within get element byclassname

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