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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
    GET is basically used for just getting (retrieving) some data from the server. Note: The GET method may return cached data.

POST can also be used to get some data from the server. However, the POST method NEVER caches data, and is often used to send data along with the request.

When to use GET

If the processing of a form is idempotent (i.e. it has no lasting observable effect on the state of the world), then the form method should be GET. Many database searches have no visible side-effects and make ideal applications of query forms.

Characteristics of GET:

Use GET for safe actions and POST for unsafe actions.

  • GET requests can be cached
  • GET requests can remain in the browser history
  • GET requests can be bookmarked
  • GET requests can be distributed & shared
  • GET requests can be hacked

When to use POST

If the service associated with the processing of a form has side effects (for example, modification of a database or subscription to a service), the method should be POST.

Use POST when dealing with long requests – if you’re sending large amounts of data, or sensitive data over HTTPS, you will want to use POST. Some browser such as Internet Explorer place a limit on the URL string so this may break the action of some forms if you use GET.

You may consider using POST for the following actions:

  • Posting a message to a bulletin board, newsgroup, mailing list, or similar group of articles
  • Providing a block of data, such as the result of submitting a form, to a data-handling process
  • Extending a database through an append operation
  • Annotation of existing resources

GET vs POST in AJAX calls

Unless you are sending sensitive data to the server or calling scripts which are processing data on the server it is more common to use GET for AJAX calls. This is because when using XMLHttpRequest browsers implement POST as a two-step process (sending the headers first and then the data). This means that GET requests are more responsive – something you need in AJAX environments! Because “Ajax” requests are subject to the same origin policy there is limited security risks when using GET instead of POST. Use GET to “GET” information from the server such as loading a JavaScript file (AJAX shorthand function $.getScript() can be used to do this) or loading a JSON file (AJAX shorthand function $.getJSON() can be used to do this).

Example :

  url: 'getTwitterFollowers.php',
  type: 'GET',
  data: 'twitterUsername=jquery4u',
  success: function(data) {
	//called when successful
  error: function(e) {
	//called when there is an error
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