It is now quite common for chemists to author web pages in HTML (leaving aside whether its better to use XML/CML etc) using entries such as e.g. Chime: <embed src=viagra.mol width=300 height=200 name=viagra BGCOLOR="white" spinx=10 spinz=10 spiny=10 startspin=true options3d=specular display3D=ball&stick alt="O=S(C1=C([H])C([H])=C(OCC)C(C(N2[H])=NC(C(CCC)=NN3C)=C3C2=O)=C1[H])(N4CCN(C )CC4)=O"> (the alt field is my own invention, but as its ignored by e.g. Chime, it does no damage, and might conceivably help some poor chemical robot index my content!) OR e.g. ChemSymphony; <APPLET archive=chemsymphony.zip code=RenderBasic.class width=200 height=200 name=model> <PARAM name=model value=models/spiro.mol> <param name=displaytype value=1> <param name=atomtype value=0> <param name=hydrogen value=1> <param name=bonds value=0> <param name=atomsradius value=0.75> <param name=bgcolor value="#000000"> <param name=scale value=1.0> OR an external Viewer (e.g Weblab Viewer from MSI) <A HREF=viagra.mol >click here to see molecule</a> The trouble is that these three ways of displaying a molecule do not "cascade", ie the user has no simple way of deciding how THEY want the molecule displayed, and if the author wants to provide that, they would have to generate the HTML dynamically (even more complicated). HTML 4 strongly deprecates these mechanisms, and instead provides a nicely cascading process (If I have read the spec correctly) <object data="viagra.mol" width="300" height="200" id="viagra" title="Viagra" style="spinx: 10; display3D: ball&stick" type="chemical/x-mdl-molfile"> <OBJECT title="Sildenafil (Viagra), C22H30N6O4S" data="sildenafil.gif" type="image/gif" width="500" height="490"> </OBJECT> 5-[2-ethoxy-5-(4-methylpiperazin-1-ylsulfonyl)phenyl]-1-methyl-3-n-propyl-1,6-di hydro-7H-pyrazolo[4,3-d]pyrimidin-7-one </object> If the browser can internally resolve chemical/x-mdl-molfile, it will display the first object; if not then the image will appear, and if you have images switched off then the molecule name will appear. Certainly makes for far more robust behaviour, and provides an abundance of chemical information about the object for index/search engines to cogitate about. BUT It does mean that much of the chemical content of the Web will be unavailable to browsers supporting HTML 4, unless they also are backwards compatible. In this regard, I have no idea if Netscape 5+ will ever support HTML 4. Does anyone know what Microsoft's policy with Internet Explorer might be? Dr Henry Rzepa, Dept. Chemistry, Imperial College, LONDON SW7 2AY; mailto:rzepa@ic.ac.uk; Tel (44) 171 594 5774; Fax: (44) 171 594 5804. URL: 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)