innerHTML with getElementByClassName doesn't work

Question

This one works:

Answer 1

It's getElementsByClassName. Note the plural s after Element.

And since it's an array you need to specify the index number.

document.getElementsByClassName('class-name')[0].innerHTML = 'html text'

And if you need to apply the change for every element, use a for loop.

for(i in document.getElementsByClassName('class-name')){
    document.getElementsByClassName('class-name')[i].innerHTML = 'html text';
}