What is Ajax?
Ajax is a programming model popularized by Google in 2005. Ajax is technically a technology rather than a language. It can update the local data of the page without refreshing the page, so as to reduce the waiting time of users when browsing information and optimize the user experience.
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Step 1: Create the request (get the Ajax object)
Step 2: Make connections
Step 3: Send the request
* Request mode:
① GET: pass the url as a parameter
② POST: The request header needs to be created. Otherwise, no data can be received
* Request file: this is the file used to receive data. PHP files are used as an example
* Request method:
① True: asynchronous request (mainstream request method)
② false: Synchronous request (hardly used)
Step 4: Receive response data Ajax status code:
① If the status code is 0, the request is not initialized
② If the status code is 1, the request is established
③ If the status code is 2, the request is received
④ If the status code is 3, the request is being processed
⑤ Status code is 4:
Request completed and ready HTTP status code:
(1) If the status code is 200, the request is successfully completed
② If the status code is 404, the page is not found
③ If the status code is 403, access is denied
Let’s demonstrate the steps of an asynchronous request in code
Share core programming techniques, V: Lezijie009 or Lezijie520 (code 21 no remarks cannot pass oh ~)
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