XHTML/HTML/JS syntax: When do I use &?

I am confused when I sh开发者_StackOverflowould use & and when I should use &, specifically when it's inside Javascript inside HTML.

Which (or both or neither) of these two URLs should use html-encoding?

<!-- Example 1 -->
<script type='text/javascript'>
    var myUrl = "myurl.html?bob=2&mary=3"; // or is it &amp;?
    downloadUrl(myUrl);
</script>

<!-- Example 2 -->
<p>Click <a href="myurl.html?bob=2&mary=3">here</a> <!-- &amp;? --> if the download doesn't start.</p>

In HTML, you should use & instead of &. In XHTML/XML, you must use & instead of &. This also applies to inline JavaScript code. This doesn't apply to JavaScript code served by fullworthy .js files unless the text becomes part of the HTML DOM tree.

In the first example it should be &. In the second it should be &