If you really want to read from Excel then there are two not so bad ways to go. If you really want to do this client side then use an HTA (HTML Application). That will only run in MSIE but with all the security down so it can read files. Better would be to have them upload the Excel to a server side script. As long as your server is running Windows and has the Jet and Excel installed then reading the files would be a snap.
“The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect.”
—Tim Berners-Lee, W3C Director and inventor of the World Wide Web