FYI I found this explanation, on
Cedrick's iWebFAQ site:
"What happens when you add an HTML Snippet to a page in iWeb is:
- iWeb creates a new page for the HTML Snippet
- iWeb adds the code you add to the Snippet into this new page
- iWeb embeds this new HTML Snippet page into the page you added the HTML Snippet to using an iFrame
Result: the code isn't where it's meant to be. The code isn't on the page you added the HTML Snippet to but is in another page which is just embedded into the page you added the Snippet to.
At times that may be satisfying/sufficient/good enough but in some cases that makes the codes not working the way they are supposed to work. This is especially true for things which need to expand like Tell a friend widgets, Highslide photos, Drop down menus, ... since HTML Snippets are iFrames with fixed sizes the codes don't get the additional room they need to display properly. That’s why it sometimes is necessary to use an alternative way to embed HTML in your iWeb created website."
I hope his eBook is still for sale