The difference between get and post

get and post The main differences are as follows ：

Essential difference ：GET It's from the server Get data ;POST Is to the server To transfer data

1、url visibility ：

get, Parameters url so ;

post,url Parameters are not visible

2、 Data transmission ：

get, By joining together url Pass parameters ;

post, adopt body Body transfer parameters

3、 Cacheability ：

get Requests can be cached

post Requests cannot be cached

4、 Back page reaction

get When requesting page back , No impact

post When requesting page back , Will resubmit the request

5、 The size of the transmitted data

get Generally, the size of the transmitted data shall not exceed 2k-4k（ Depending on the browser , Restrictions are different , But it's not much different ）

post The size of the requested transfer data is based on php.ini Profile settings , It can be infinite .

6、 Security

This is also the most difficult to analyze , In principle, post It must be better than get Security , After all, when transmitting parameters url invisible , But it can't stop some people from grabbing bags and playing when they are free . The security individual feels is not much different , That's why we should guard against gentlemen and villains . Encrypt the passed parameters , It's all the same .

7、 Data packets

GET Produce a TCP Data packets ;POST Produce two TCP Data packets . about GET Method request , The browser will http header and data Send along , Server response 200（ Return the data ）; And for POST, Browser sends first header, Server response 100 continue, The browser sends data, Server response 200 ok（ Return the data ）. In a good network environment , The difference between the time to send a packet and the time to send two packets is negligible . And in the case of bad network environment , The two packages TCP On verifying packet integrity , It has great advantages . Not all browsers will be there POST Send two packets in ,Firefox Just send it once .