Re: Is there any antivirus to be imstalled for nokia lumia-520? If so what will be the right choice
The antivirus is supplied by Microsoft's Windows Phone Store - all apps are checked and scanned before they hit your phone, so there is no need for your phone to have any anti-virus apps.
Internet Explorer on the phone won't allow scripts to access any data on your phone. If you happen to hit a page with a malicious script, the most that will happen is the page will crash.