HTTP Methods: GET vs. POST

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

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