It says that TypeError: document.getElementById(...) is null [duplicate]

Question

Althought I pushed a parameter to getElementById I wonder from where is this 'is null' error coming from?

TypeError: document.getElementById(...) is null [Break On This Error]     document.getElementById(elmId).innerHTML = value;  Line 75   

In addition to this i wonder why title and time did not show unless I click one of these playlist pictures?

Answer 1

Make sure the script is placed in the bottom of the BODY element of the document you're trying to manipulate, not in the HEAD element or placed before any of the elements you want to "get".

It does not matter if you import the script or if it's inline, the important thing is the placing. You don't have to put the command inside a function either; while it's good practice you can just call it directly, it works just fine.

Answer 2

All these results in null:

document.getElementById('volume'); document.getElementById('bytesLoaded'); document.getElementById('startBytes'); document.getElementById('bytesTotal'); 

You need to do a null check in updateHTML like this:

function updateHTML(elmId, value) {   var elem = document.getElementById(elmId);   if(typeof elem !== 'undefined' && elem !== null) {     elem.innerHTML = value;   } }