It's probably a configuration issue with your webserver, or incorrect placement of the script within your server's filestructure. If the server is properly configured, and the script is where it belongs, or otherwise identified as a CGI script such that your webserver knows what to do with it, there should be no way for any sort of browser (mis)configuration to ever see the actual code behind the CGI script.

It's the web server's responsibility to execute a CGI script. If it's failing to do so, it's not the browser's fault. Somehow you're not identifying to your webserver that the CGI script is a CGI script. Instead, it's thinking it is just some file, and handing it un-executed to the browser. The browser reacts by asking if you want to save this file.

The second issue is that of your error message when you run it from the command line:

Undefined subroutine &main::pram called at ./Write.cgi line 15

Unless your script defines a subroutine named pram(), my guess is that you really mean to be calling param() on line 15 of your script named Write.cgi.