Webplayer Plug-in?

I’d like to know if there is a plug-in or anything that I can run data which I can save in temporary folders/documents like
Internet catch data when I run web player without running large bundle files on the web at first time.

When Unity content is fetched from the internet it is cached by the web browser. AssetBundles can be decompressed and written into a Unity cache. See:

http://unity3d.com/support/documentation/ScriptReference/WWW.LoadFromCacheOrDownload.html

The Unity webplayer has no direct access to the hard drive of the machine where it is running.