There's a list of supported tags and attributes here. Any other tags/attributes should be gracefully ignored. Please let us know:
If anything claimed to be supported doesn't work properly.
If anything not claimed to work seems to mess up supported elements.
If possible, please send us a copy of the HTML page being displayed.
Display is based as closely as possible on Internet Explorer 5's interpretation of HTML - we've tried to match page layout. However, WebShow is not a browser, and doesn't pretend to conform to any W3C HTML specification. In particular, note that tables are not supported (although content contained in tables will still be rendered as if there were no table tags).
The browser limits the memory available for running a Java applet, and very long documents may be only partially rendered. There should be no problem with pages up to about 20 Kb, but we recommend keeping to a maximum document size of 10 Kb (which is still a long document!).
Pages only scroll if they need to. If a page is short enough to be shown in the applet without scrolling, it will be static.
Any <br> and <p> tags appearing before any text on the page are automatically discarded. So if the page begins with non-displayable content (such as an <object>, <applet> or <embed> tag) followed by some white space, the space will be removed.
Pages load v-e-r-y s-l-o-w-l-y in later Netscape 4 editions (4.5+, 4.06+, which are the editions of Netscape that use Java VM version 1.1.5). This JVM version is bad even by Netscape's standards, and it processes at a snail's pace. If you have the patience, the pages will load eventually, but this JVM can take 2 to 3 minutes [sic] to render a page that Internet Explorer's JVM renders in under one second. In earlier Netscape 4s, Netscape 3, Netscape 6 and Opera, the applet will render most pages in under 2 seconds.