Since JavaScript cannot be relied upon to work for everyone (client-side) the php (server-side) include is a much better option.
I have some good amateur experience with basic-to-intermediate HTML and CSS, but my experience with JavaScript and conditional comments is nonexistent. I'm working on developing a site and I want to use some sort of automated process to put code for a navigation bar on every page. I tried the trick described here: http://webdesign.about.com/od/javascript/ht/htjsincludehtm.htm but it's not showing up on IE9, though it does work in Chrome and it seems to work on older versions of IE. I don't really have the option of doing anything server-side due to the nature of the project. Is there a way to get this to work in IE9, or can I at least get help on some other way to achieve what I'm looking for?

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