It turns out that the server only detects the user agent of your browser, especially your os type info in the user agent tag. Then they will give you the safe connect software according to your os type.
Luckily, they don't have a iPad version of Safe Connect, leaving me some opportunities to bypass the system. The user agent info is defined by HTTP request header, so the main task is to block the http request when the browser tries to connect to the school's server.
I made that in Chrome. It only has around thirty lines of code. What it does is to modify the HTTP request header when the request is send to school's server. By fooling the system, the users can bypass the safe connect.
However, due to security concern, I will not release the Chrome extension publicly as Safe Connect is part of anti-piracy system.