Installing Security Certificates Once

I've found a script on the MS site that allows me to install a security
certificate for my SSL connections. The problem is that I have set it
up on the index.htm. So now users are prompted to accept installation
of my certificate everytime instead of the normal trust certificate
yes/no dialog. I don't want my users to be prompted if they've already
installed.

Is there any way to script the page to check for the certificate being
installed then be able to install or skip and re-direct to the secure
login page.