JavaScript is a scripting language that can run wherever there is a suitable script interpreter such as web browsers, web servers, or the Windows Scripting Host. The scripting environment used to run JavaScript greatly affects the security of the host machine: A web page with JavaScript runs within a web browser in much the same way as Java applets and does not have access to host machine resources. An Active Server Page (ASP) or a Windows Scripting Host (WSH) script containing JavaScript is potentially hazardous since these environments allow scripts unrestricted access to machine resources (file system, registry, etc. ) and application objects.