Possible to check for files on users computer from website?

I know this question brings up a lot of security issues, but is it possible to check for files on a user's HD from a website? We have a开发者_如何学JAVA software application and would like to be able to check for certain files-types on the user's cpu before they download our software.

Again, I realize this is intrusive and a security issue but wanted to ask anyway. If this is possible, would it be done with some type of Java or ActiveX control?

I would appreciate anyone pointing us in the right direction. thx!

I suppose using either Java or ActiveX would work, but only where Java or ActiveX exist. Obviously, users of browsers other then IE don't get ActiveX, and I'm not sure the penetration of Java, or Java Webstart installs. I'm sure its not anywhere near everyone.

If your goal is to validate a system before installing some complex software with dependencies, I would suggest having a separate package that just does the validation. Especially if it is just a single .exe (not requiring installation), spending 30 seconds doing this in prep for some complex download, install, reboot, fail cycle seems like a good tradeoff.

It can be done with an ActiveX control. The user would, of course, be prompted for permission for this, but since sites like Panda Security can do a virus check via an ActiveX control, then it's definitely possibe to write one to list the files on a HD.

I'm not sure if the Java Sandbox will allow this, so I'll defer the question of doing this via a Java Applet to REAL Java developers. (I haven't been a Java developer since 1.14, and I was never any good at it.)

Java Web start can do this with the proper settings http://www.ibm.com/developerworks/java/library/j-webstart/