This User Login System System Sequence Diagram is an excellent example of a sequence diagram. Any login page involves messages being sent back and forth, objects being activated, and data being responded to over a specific period. That is precisely what a sequence diagram is intended to demonstrate. After the page loads, you're usually presented with a form where you can enter your credentials or the information you used to sign up for the site. Typically, this is just your email address and a password. When you enter your information and submit the form, the sequence diagram comes into play and demonstrates how useful it can be.
