The best way to deal with it is to follow all the recommendations 
Start of to fix the easy ones, the first one for example, you just need to specify the attribute.
The problem I think is mainly in one component or mod where the coder was not particalurly interested in valid html, this one is particularly easy to fix,Line 2276, Column 30: required attribute "type" not specified
<script language="javascript">✉
The attribute given above is required for an element that you've used, but you have omitted it. For instance, in most HTML and XHTML document types the "type" attribute is required on the "script" element and the "alt" attribute is required for the "img" element.
Typical values for type are type="text/css" for <style> and type="text/javascript" for <script>.
do a codesearch for<script language="javascript">
and simply replace with<script type="text/javascript">
Codesearch is easily done for an entire site with dreamweaver, so if you don't have that, get a trial version and work with that.
Then read up on how to alter the javascripts itself, there are the most errors.
Adding CDATA to the javascript will also make a difference, if it is not already there.
It will exclude javascript from the browser its parser, so it will validate easier.
I hope that helps.