html - what is the meaning of ?(question mark) in url string?

Question

can someone explain what is the difference between using
href="../usermanagement/search_user.jsp?" and
href="../usermanagement/search_user.jsp?pagename=navigation"
in navigation.jsp.

question from:https://stackoverflow.com/questions/33041449/what-is-the-meaning-of-question-mark-in-url-string

Answer 1

Its name is Query string. After the question mark you can pass key-value pairs and use them server-side.

https://en.wikipedia.org/wiki/Query_string