Code works in W3shool test page but not in Joomla - toggle

Question

I am testing this code and it is working here http://www.w3schools.com/js/tryit.asp?filename=tryjs_debugger but not on my Joomla page. The Chrome console error is at the bottom of the post
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"></script>
<script type="text/javascript">
function toggleDiv(divId) {
$("#"+divId).toggle();
}
</script>
Toggle Button
<div id="myContent" style="background-color: #aaa; padding: 5px 10px;">
The content in this div will hide and show (toggle) when the toggle is pressed.
</div>
63-tet.html:168 Uncaught TypeError: Cannot read property 'toggle' of nulltoggleDiv # 63-tet.html:168(anonymous function) # VM4704:1
I have cheched the source page and my code is sent back to me by the server untouched:
<div itemprop="articleBody">
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"></script>
<script type="text/javascript">
function toggleDiv(divId) {
$("#"+divId).toggle();
}
</script>
Toggle Button
<div id="myContent" style="background-color: #aaa; padding: 5px 10px;">
The content in this div will hide and show (toggle) when the toggle is pressed.
</div> </div>

Answer 1

It sounds like Joomla is filtering/ black-listing certain keywords. You can see that it is trying to call the function:
nulltoggleDiv and access the toggle property of that.
If you press f12 and search for "toggleDiv" you should be able to see the actual html after it has been deformed.
Check out this document:
https://docs.joomla.org/Help16:Content_Article_Manager#Filtering_Options_.28HTML.29
from doc:
Black List Filters
The default filter method in Joomla! is 'Black List'. The default 'Black List' contains the following tags to exclude:
'applet', 'body', 'bgsound', 'base', 'basefont', 'embed', 'frame', 'frameset', 'head', 'html', 'id', 'iframe', 'ilayer', 'layer', 'link', 'meta', 'name', 'object', 'script', 'style', 'title', 'xml'
The default 'Black List' contains the following attributes to exclude:
'action', 'background', 'codebase', 'dynsrc', 'lowsrc'
You can 'Black List' (disallow) additional tags and attributes by adding to the Filter tags and Filter attributes fields, separating each tag or attribute name with a space or comma. If you select a Filter Type of "Black List", this list will always be used, plus any additional tags and attributes you add.

Answer 2

The problems seems to be with this reference
$("#"+divId).toggle();
After I replaced the above with
var element = document.getElementById(divId);
element.toggle();
the code worked