Follow the steps given below to browse facebook using secure connection.
Step 1 : Click on Account menu at the top right corner.
Step 2 : In that click Account Settings option.
Step 3 : On the settings tab click on Account Security option
Step 4 : Check "Browse Facebook on a secure connection (https) whenever possible" box.
Click on Save and you are done.
After completing procedure you will see https://www.facebook.com instead of http://www.facebook.com. This indicates that you are browsing facebook on secure connection. It makes your connection encrypted by using SSL/TLS protocols so protects you from the eavesdropping and intercepting your data by someone for malicious purpose.
The other option is of Login Notifications .
It will notify you when you try to log in to your facebook account using different computer/IP address.
There are two notification options.
1.Send me an Email
When you try to log in using different computer/IP address, facebook will notify you about your log in attempt by sending you an email
2.Send me a text message
When you try to log in using different computer/IP address, facebook will notify you about your log in attempt by sending you a text message on mobile no you have specified in your facebook account.
You can also enable secure browsing in Gmail. Read how to make facebook connection secure here