Detecting browser SSL capability with JavaScript

If you run a secured website using HTTPS (aka SSL) it’s often wise to stop or notify users that are using a browser or client that doesn’t support the proper encryption level required.

Here’s a short method to “sniff” the capabilities prior to forwarding users to the secure area. You could add logic to inform the user of the problem.

As usual I’ve stripped a lot of the XHTML markup for readability.

<!– set ‘sslok’ global variable for testing SSL capability –>
<script type=”text/javascript”>
var sslok = 0;
<!– try including source javascript from secure server, this will set “sslok” to 1 if it works –>
<!– note that the /secure directory is protected so that only 128+bit SSL is allowed –>
<script type=”text/javascript” src=””></script>
<!– if ssl is 1, our javascript include worked, so SSL is successful – redirect to SSL –>
<script type=”text/javascript”>
if (sslok == ‘1’) {
window.location = ‘’;

Contents of the ‘ssl-test.js’ file:

<!– set sslok to 1, so we know this include succeeded –>
sslok = ‘1’;

NOTE: If you use the same ‘filesystem’ for HTTP & HTTPS you might want to use a server-side program (PHP or Java for example) to generate the JavaScript.  Benefit of that process would be that you could also interrogate and return other SSL attributes such as cypher strength.


Enabling A Secure Apache Server w/SSL Certificates

If you’ve taken some time to wander around my site, you may have noticed that I also have SSL enabled (with url’s). Here’s the steps you can take on your site/server – provided you have proper access.

Download and install Apache-OpenSSL and OpenSSL – I’ve found to be a reliable source for precompiled binaries for Win32 platforms.

Install OpenSSL, and add the following environmental variable.
OPENSSL_CONF=[apache_root]/bin/openssl.conf (.cnf?)

Generate a private key:
openssl genrsa —des3 —out filename.key 1024

Create CSR Request…
openssl req —new —key filename.key —out filename.csr

This step will ask for several pieces of information, here’s my example:

Country Name (2 letter code) [AU]:US
State or Province Name (full name) [Some-State]:Illinois
Locality Name (eg, city) []:Carol Stream
Organization Name (eg, company) [Internet Widgits Pty Ltd]:Dean Scott Fredrickson
Organizational Unit Name (eg, section) []:Giant Geek Communications
Common Name (eg, YOUR name) []
Email Address []:[email protected]
Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:xxxxxxxxxxxxxx
An optional company name []:Giant Geek Communications

You can now send this CSR to a valid Certifying Authority…
I currently use

It’s very likely that the CA will need to verify your identity, typically this requires you to fax a copy of your id card/passport or business papers. A D-U-N-S Number (from Dun and Bradstreet) will make this easier for businesses.

If you don’t plan on having lots of users, you can create a Self-signed certificate…
openssl x509 —req —days 30 —in filename.csr —signkey filename.key —out filename.crt

You’ll need to install the files received from the CA, but it’s pretty trivial so I’ll leave it for later.