jquery $.post【2014-11-10】
jQuery.post()
jQuery.post( url [, data ] [, success ] [, dataType ] )Returns:jqXHR
Description: Load data from the server using a HTTP POST request.
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version added:1.0jQuery.post( url [, data ] [, success ] [, dataType ] )
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urlType: StringA string containing the URL to which the request is sent.
- //解释一下:URL是必选的参数,其余参数可选。URL是request请求的路径。
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dataType: PlainObject or StringA plain object or string that is sent to the server with the request.
- //解释一下:data是浏览器通过request请求向服务器发送一些参数,这个参数的类型可以是字符串类型,也可是plainObject类(感觉和Java中Object差不多)。
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successA callback function that is executed if the request succeeds. Required if
dataType
is provided, but can benull
in that case. - //解释一下:success是request请求成功后触发的回调函数。
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dataTypeType: StringThe type of data expected from the server. Default: Intelligent Guess (xml, json, script, text, html).
- //解释一下:dataType是从服务器返回的类型,可以是XML、json、script、text、HTML。
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This is a shorthand Ajax function, which is equivalent to:
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The success
callback function is passed the returned data, which will be an XML root element or a text string depending on the MIME type of the response. It is also passed the text status of the response.
//解释一下:上面的$.post可以用$.ajax来替代。
As of jQuery 1.5, the success
callback function is also passed a"jqXHR" object (injQuery 1.4,
it was passed the XMLHttpRequest
object).
Most implementations will specify a success handler:
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This example fetches the requested HTML snippet and inserts it on the page.
Pages fetched with POST
are never cached, so thecache
and
ifModified
options in jQuery.ajaxSetup()
have no effect on these requests.
//解释一下:自从jQuery1.5后是用的jqXHR 对象,而以前的版本是用的XMLHttpRequest对象。通过post方法获取的数据不会缓存。
The jqXHR Object
As of jQuery 1.5, all of jQuery‘s Ajax methods return a superset of theXMLHTTPRequest
object. This jQuery XHR object, or "jqXHR," returned by$.get()
implements the Promise interface,
giving it all the properties, methods, and behavior of a Promise (seeDeferred object for more information). ThejqXHR.done()
(for success),
jqXHR.fail()
(for error), andjqXHR.always()
(for completion, whether success or error) methods take a function argument that is called when the request terminates. For information about the arguments this function receives, see thejqXHR
Object section of the $.ajax() documentation.
The Promise interface also allows jQuery‘s Ajax methods, including$.get()
, to chain multiple
.done()
, .fail()
, and.always()
callbacks on a single request, and even to assign these callbacks after the request may have completed. If the request is already complete, the callback is fired immediately.
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//解释一下:向example.php发送请求如果成功就弹出success,如果发送两次都成功了,就弹出second success;如果失败,弹出error;如果完成,弹出finished等。这里的done就是请求成功后执行的函数,fail就是请求失败后执行的函数,always就是无论请求成功还是失败都要执行的函数。
Deprecation Notice
The jqXHR.success()
, jqXHR.error()
, andjqXHR.complete()
callback methods introduced in jQuery 1.5 are
deprecated as of jQuery 1.8. To prepare your code for their eventual removal, usejqXHR.done()
,
jqXHR.fail()
, and jqXHR.always()
instead.
//解释一下:success、error和complete方法是在jQuery1.5中出现的,现在不推荐使用,推荐用done、fail、always来代替这些函数。
Additional Notes:
- Due to browser security restrictions, most "Ajax" requests are subject to thesame origin policy; the request can not successfully retrieve data from a different domain, subdomain, port, or protocol.
- If a request with jQuery.post() returns an error code, it will fail silently unless the script has also called the global.ajaxError()
method. Alternatively, as of jQuery 1.5, the
.error()
method of thejqXHR
object returned by jQuery.post() is also available for error handling. - //解释一下:由于浏览器的安全策略,来自不同的域,子域、端口和协议时,获取数据可能不成功。
Examples:
Example: Request the test.php page, but ignore the return results.
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Example: Request the test.php page and send some additional data along (while still ignoring the return results).
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Example: Pass arrays of data to the server (while still ignoring the return results).
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Example: Send form data using ajax requests
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Example: Alert the results from requesting test.php (HTML or XML, depending on what was returned).
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Example: Alert the results from requesting test.php with an additional payload of data (HTML or XML, depending on what was returned).
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Example: Post to the test.php page and get content which has been returned in json format (<?php echo json_encode(array("name"=>"John","time"=>"2pm")); ?>).
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//解释一下:上面是post方法的一些简单举例,涉及的东西还是上面讲到的。
Example: Post a form using ajax and put results in a div
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