In IE, jQuery's presence causes other scripts using 'defer' to not run at all

[dave@…]

In IE7 and IE8, when jQuery 1.4.3 - 1.7.1 is present in a page, an unrelated script that has a defer attribute won't execute at all, if that script takes a while to load.

Example: ​http://brondsema.net/tmp/jquery_script_defer.html

• jQuery 1.4.2 does not exhibit this behavior. Something introduced in 1.4.3 triggers it.
• IE9 does not exhibit this behavior. Something was fixed in IE9
• if the 'defer' script loads quickly (e.g. before domready or something like that), then it will execute.
• Dynamically inserting a script DOM element that has defer=true does not exhibit this behavior. It is only when using the script tag and defer attribute in the HTML.

[dmethvin]

Duplicate of #11310.