I want to test websites for JavaScript malware presence . I plan to develop a Python program that sends the URL of a given website to a virtual machine where the dynamic execution of the eventual malicious JavaScript embedded in the website's page is monitored. My questions:

1. Should my VM be Windows or Linux ?
2. What if the malware damages my VM: is there a hint how to avoid that ? Or launch a new VM automatically instead ?
3. If I use telnet client library to communicate with the VM: must I implement a server within the VM to deal with my queries or can I overcome this ?

I am jut looing for hints, general ideas. Thank you for any help.