To sum up the results: most people haven't a clue what a pdb file is. Meaning careful consideration about the audience of a site is required when using special file formats. If you have control of your users (i.e., a group of students in a univ lab) then OK), but if you don't - beware, and test your pages using several hardware/software configurations.
To follow up Mark's comment, this is an area where HTML was not thought out too well in its original implementation. Basically, the system is not "fail safe". The HTML 4.0 and the recommended XHTML spec does allow for better (but not perfect) treatment of this issue, via something like <object> <object 2 if object 1 cannot be displayed> <object 3 if 1 and 2 cannot be displayed> Text if none of the objects can be displayed </object> </object> </object> Object 3 could be an image, 2 say a Java object and 1 say a Chime object. Needless to say, the above construct is not supported uniformly. The excellent iCab browser for Mac supports it fully, Netscape does a pretty good job, but IE appears to try to display ALL the objects simultaneously (and also ignores any parameters declared in association with the object). One also has a breed of what might be called "hidden" browser, ie part of an AOL suite, where such "advanced" options are again indifferently supported If one takes the premise that authors must support the lowest common denominator, then all of the above fails, and we must revert to the patchy implementations, which causes problems of the type Mark refers to. -- Henry Rzepa. +44 (0)20 7594 5774 (Office) +44 (0870) 132-3747 (eFax) Dept. Chemistry, Imperial College, London, SW7 2AY, UK. http://www.ch.ic.ac.uk/rzepa/ chemweb: A list for Chemical Applications of the Internet. To post to list: mailto:chemweb@ic.ac.uk Archived as: http://www.lists.ic.ac.uk/hypermail/chemweb/ To (un)subscribe, mailto:majordomo@ic.ac.uk the following message; (un)subscribe chemweb List coordinator, Henry Rzepa (mailto:rzepa@ic.ac.uk)