1."GET" is used to get data from server, as we know , before we want to get some date from server ,we should tell server what we want,with this mechanism , we ofen use "GET" to post few data. There are some limiation when we use "GET":
a. The data in "GET" is encolosed in the "QUERY-STRING " environment variable , and then it is send to server as part of the whole URL, so the "GET" data will be unsafely exposed in the browser's URL address zone insecurely.
b. The storage space of "QUERY-STRING" variable is limited, which means that some data will be lost if the data is too large.
2. "POST" is used to post data to server, the data is contained in the content of HTTP REQUEST whie "GET" transmit it's variables in the head of HTTP REQUEST. With "POST", we can post as much data to server as we want.
ps:
1. If the action address of "GET" is self page, the server will treat it as a new Page, the page's viewsate will be lost. By contraries,if we "POST" the self page, the page's viewsate will still exist.
2. When we upload some pictures to server, we should use "POST", and the "enctype", a attribute of the form, the MIME encode, must be set as " ENCTYPE="multipart/form-data" ", while default setting is "ENCTYPE=application/x-www-form-urlencoded", then the input data of form use binary transfers.
3. Instead of "Request.QueryString[]" when we want to get the data of "GET" , we use "Request.Form[]" to get the data of "POST".
4. For more infomation about "GET" and "POST", please see http://www.cs.tut.fi/~jkorpela/forms/methods.html