How to write a simple function (to run on scene load) to target element with a particular class

I got the reason why it did not work :

we have to define in a stylesheet file or in the document head / I defined an opacity attr. in the / “.mm” / class in the style in order for it to work.

as I was testing the result is for only the first instance of any element that have this class name . If we have / which is very normal / more than one element with the same class only one is affected ?

the weird thing is that the first occurrence of the class attached to any element is ; its presence from the top of the document down??? its Y coordinate ??

@kamal I am sorry but I can’t micromanage your learning. You have to read on the internet. Please look up the things I wrote about. querySelector (=first match) querySelectorAll (=list). With a list you have to write a loop … just read about it on the web. Good luck!