The example in this article describes the implementation method of PHP real-time countdown function. I would like to share it with you for your reference. The details are as follows:

In the past few days, the company will have a limited time shopping function. This requires a countdown and a real-time countdown.

Requirements:

1) There must be a real-time countdown display of hours, minutes and seconds
2) Modifying the date and time on the client side will not affect the normal display of the countdown (that is, based on server time) Subject)

In fact, this has the same requirements as the time limit function of many examination and other systems.

Solution ideas:

1) It cannot always be Use ajax to get the server time every second.

So the real-time countdown must be implemented with javascript. This is very simple. There are a lot of examples on the Internet.

2) Now the problem is to solve the problem on the client side The impact of modifying the date and time on our display.
The solution is to calculate the time difference between the client time and the server time. This solves the problem.

In this way, you only need to run php once. Real-time countdown The time is synchronized with the server's time.

Theoretically it is synchronized, but in actual testing there will be an error of 1 second. (The specific reason is related to the network speed. The faster the network speed, the smaller the error). But this will never affect our above requirements.

Example:

Code:

       
  
XX:XX:XX
  

Example 2:

Modified some of the above bugs

Code:

       
  
XX:XX:XX
  

Example 3:

The idea is different, much simpler.

Code:

       
  
XX:XX:XX
  

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