Stripping class from HTML tags

HI all,

I'm surprised this didn't come up in my search results, as I thought this would be a common question. I use openoffice to create documents, and I want to save time in producing an html version which will go on a CMS. As most will probably guess, the HTML openoffice exports is pretty poop, and I want to clean it up.

All I want is simple html tags, eg

<h1> instead of <h1 class="P12"> and <p> instead of <p class="P3">

I don't know regex or preg_replace but I know it can do what I want.
Can anyone help?

Sure, this is an excellent starting point:
http://www.regular-expressions.info/tutorial.html