Detailed look at the bloggers
https://segmentfault.com/a/1190000012878173
There is a need to get the time function, originally acquired the client time, but the client may encounter a malicious user to change the time during development, so I plan to get the server time.
Principle: When using ajax request, return the header information contains the time information of the server, acquires the time data in the header information in the return information to
