我们可以在$.post中像这样更改Content-type

$.post(url,data, function (data, status, xhr) {
    xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded; charset=utf-8");});

只使用

jQuery.ajax ({
    url: myurl,
    type: "POST",
    data: mydata,
    dataType: "json",
    contentType: "application/json; charset=utf-8",
    success: function(){
        //
    }
});

更新@JK:如果你在你的问题中只写一个带有$的代码示例。你在答案中找到一个相应的例子。我不想重复同样的信息，你已经学习了，直到知道:$。Post和$。Get是$.ajax的缩写形式。所以只需使用$。Ajax，您可以使用它的全部参数集，而无需更改任何全局设置。

By the way I wouldn't recommend overwriting the standard $.post. It's my personal opinion, but for me it's important, not only that the program works, but also that all who read your program understand it with the same way. Overwriting standard methods without having a very important reason can follow to misunderstanding in reading of the program code. So I repeat my recommendation one more time: just use the original $.ajax form jQuery instead of jQuery.get and jQuery.post and you receive programs which not only perfectly work, but can be read by people without any misunderstandings.

你猜怎么着?@BenCreasy完全正确!!

从jQuery 1.12.0版本开始，我们可以这样做:

$.post({
    url: yourURL,
    data: yourData,
    contentType: 'application/json; charset=utf-8'
})
    .done(function (response) {
        //Do something on success response...
    });

我刚刚测试了一下，它工作了!!

$.ajax({
  url:url,
  type:"POST",
  data:data,
  contentType:"application/json; charset=utf-8",
  dataType:"json",
  success: function(){
    ...
  }
})

参见:jQuery.ajax()

我知道这是一个晚的答案，我实际上有一个快捷的方法，我用来发布/读取/从基于MS的服务。它与MVC以及ASMX等工作…

Use:

$.msajax(
  '/services/someservice.asmx/SomeMethod'
  ,{}  /*empty object for nothing, or object to send as Application/JSON */
  ,function(data,jqXHR) {
    //use the data from the response.
  }
  ,function(err,jqXHR) {
    //additional error handling.
  }
);

//sends a json request to an ASMX or WCF service configured to reply to JSON requests.
(function ($) {
  var tries = 0; //IE9 seems to error out the first ajax call sometimes... will retry up to 5 times

  $.msajax = function (url, data, onSuccess, onError) {
    return $.ajax({
      'type': "POST"
      , 'url': url
      , 'contentType': "application/json"
      , 'dataType': "json"
      , 'data': typeof data == "string" ? data : JSON.stringify(data || {})
      ,beforeSend: function(jqXHR) {
        jqXHR.setRequestHeader("X-MicrosoftAjax","Delta=true");
      }
      , 'complete': function(jqXHR, textStatus) {
        handleResponse(jqXHR, textStatus, onSuccess, onError, function(){
          setTimeout(function(){
            $.msajax(url, data, onSuccess, onError);
          }, 100 * tries); //try again
        });
      }
    });
  }

  $.msajax.defaultErrorMessage = "Error retreiving data.";


  function logError(err, errorHandler, jqXHR) {
    tries = 0; //reset counter - handling error response

    //normalize error message
    if (typeof err == "string") err = { 'Message': err };

    if (console && console.debug && console.dir) {
      console.debug("ERROR processing jQuery.msajax request.");
      console.dir({ 'details': { 'error': err, 'jqXHR':jqXHR } });
    }

    try {
      errorHandler(err, jqXHR);
    } catch (e) {}
    return;
  }


  function handleResponse(jqXHR, textStatus, onSuccess, onError, onRetry) {
    var ret = null;
    var reterr = null;
    try {
      //error from jqXHR
      if (textStatus == "error") {
        var errmsg = $.msajax.defaultErrorMessage || "Error retreiving data.";

        //check for error response from the server
        if (jqXHR.status >= 300 && jqXHR.status < 600) {
          return logError( jqXHR.statusText || msg, onError, jqXHR);
        }

        if (tries++ < 5) return onRetry();

        return logError( msg, onError, jqXHR);
      }

      //not an error response, reset try counter
      tries = 0;

      //check for a redirect from server (usually authentication token expiration).
      if (jqXHR.responseText.indexOf("|pageRedirect||") > 0) {
        location.href = decodeURIComponent(jqXHR.responseText.split("|pageRedirect||")[1].split("|")[0]).split('?')[0];
        return;
      }

      //parse response using ajax enabled parser (if available)
      ret = ((JSON && JSON.parseAjax) || $.parseJSON)(jqXHR.responseText);

      //invalid response
      if (!ret) throw jqXHR.responseText;  

      // d property wrap as of .Net 3.5
      if (ret.d) ret = ret.d;

      //has an error
      reterr = (ret && (ret.error || ret.Error)) || null; //specifically returned an "error"

      if (ret && ret.ExceptionType) { //Microsoft Webservice Exception Response
        reterr = ret
      }

    } catch (err) {
      reterr = {
        'Message': $.msajax.defaultErrorMessage || "Error retreiving data."
        ,'debug': err
      }
    }

    //perform final logic outside try/catch, was catching error in onSuccess/onError callbacks
    if (reterr) {
      logError(reterr, onError, jqXHR);
      return;
    }

    onSuccess(ret, jqXHR);
  }

} (jQuery));

注意:我还有一个JSON。parseAjax方法是修改自json.org的JS文件，它增加了处理MS“/Date(…)/”日期…

修改后的json2.js文件不包括在内，它在IE8的情况下使用基于脚本的解析器，因为当你扩展数组和/或对象的原型时，本地解析器会中断，等等。

我一直在考虑修改这段代码以实现承诺接口，但它对我来说工作得非常好。

出于某种原因，在ajax请求上设置@Adrien建议的内容类型在我的情况下不起作用。但是，您实际上可以使用$更改内容类型。在发布之前这样做:

$.ajaxSetup({
    'beforeSend' : function(xhr) {
        xhr.overrideMimeType('application/json; charset=utf-8');
    },
});

然后赚你的美元。post调用:

$.post(url, data, function(), "json")

我有jQuery + IIS的问题，这是唯一的解决方案，帮助jQuery理解使用windows-1252编码ajax请求。