Squid has a proxy server

Such as TCP/IP is now 100.100.100.100
I the web site, the browser will set up a proxy server 100.100.100.100, port 80

But tomorrow the proxy server IP into 100.100.100.101
The browser will change 100.100.100.101 agent, port 80

The day after tomorrow the proxy server IP into 100.100.100.102
The browser's proxy Settings to change 100.100.100.102 port 80

I mean, I have no way to get into port mapping, the server IP has changed, the browser Settings do not need to change, you can continue to acting, don't every time to modify the proxy Settings