The login and exit code for Taobao website is not understood

If ($ _ GET [& quot; op & quot;] & amp; $ _ GET [& quot; op & quot;] & quot; logout & quot;) {unset ($ _ SESSION [& quot; user & quot;]);} if ($ _ GET ["op"] & $ _ GET ["op"] = "logout ") {unset ($ _ SESSION ["user"]);}
Do not understand the condition statements in if

Reply content:

If ($ _ GET ["op"] & $ _ GET ["op"] = "logout") {unset ($ _ SESSION ["user"]);}
Do not understand the condition statements in if

If there is an operation (op) and the operation is logout, the session will be cleared.

Hope to help ~ :)