Two commonly used methods for a request-response between a client and server are: GET and POST.
- GET - Requests data from a specified resource
- POST - Submits data to be processed to a specified resource
The GET Method
Note that query strings (name/value pairs) is sent in the URL of a GET request:
/test/demo_form.asp?name1=value1&name2=value2
Some other notes on GET requests:
- GET requests can be cached/GET请求可以被缓存
- GET requests remain in the browser history/GET请求保存在浏览器历史中
- GET requests can be bookmarked/GET请求可以被保存为书签
- GET requests should never be used when dealing with sensitive data/GET请求不能用来处理敏感数据
- GET requests have length restrictions/GET请求有数据长度限制
- GET requests should be used only to data/GET请求应该被用来获取数据
The POST Method
Note that query strings (name/value pairs) is sent in the HTTP message body of a POST request:
POST /test/demo_form.asp HTTP/1.1
Host: w3schools.com
name1=value1&name2=value2
Host: w3schools.com
name1=value1&name2=value2
Some other notes on POST requests:
- POST requests are never cached/POST请求不会被缓存
- POST requests do not remain in the browser history/POST请求不会保存在浏览器历史中
- POST requests cannot be bookmarked/POST请求不能被存为标签
- POST requests have no restrictions on data length/POST请求没有数据长度限制
Compare GET vs. POST
The following table compares the two HTTP methods: GET and POST.
| GET | POST | |
|---|---|---|
| BACK button/Reload | Harmless | Data will be re-submitted (the browser should alert the user that the data are about to be re-submitted) |
| Bookmarked | Can be bookmarked | Cannot be bookmarked |
| Cached | Can be cached | Not cached |
| Encoding type | application/x-www-form-urlencoded | application/x-www-form-urlencoded or multipart/form-data. Use multipart encoding for binary data |
| History | Parameters remain in browser history | Parameters are not saved in browser history |
| Restrictions on data length | Yes, when sending data, the GET method adds the data to the URL; and the length of a URL is limited (maximum URL length is 2048 characters) | No restrictions |
| Restrictions on data type | Only ASCII characters allowed | No restrictions. Binary data is also allowed |
| Security | GET is less secure compared to POST because data sent is part of the URL Never use GET when sending passwords or other sensitive information! |
POST is a little safer than GET because the parameters are not stored in browser history or in web server logs |
| Visibility | Data is visible to everyone in the URL | Data is not displayed in the URL |
源地址:http://www.w3schools.com/tags/ref_httpmethods.asp