Javascript not triggering

Hi all,

I have a simple piece javascript code to keep the scroll bar of a container in the down position when you view it (because default is in the up position):

var x = document.getElementsByClassName("dataViewConversation")[0];
 x.scrollTop = x.scrollHeight;
 

Problem is that when I use either the HTML snippet or JavaScript Snippet available in the app store the js does not trigger on view, but I know it works because I tried it with the javascript button to manually trigger and it works fine. Any ideas?