Ajax：预检的响应具有无效的HTTP状态代码404

Question

我有服务，当我称之为 我收到错误，预检的响应有无效的HTTP状态代码404，如下图所示。 请在这里解决这个问题 谢谢

这是ajax

    $.ajax({
        url:url,
        type: "Get",
        async: true,
        contentType: "application/text",
        dataType: "json",
        cache: false,
        crossDomain: true,
        success: function (data) {

        }

        }
    });

的Web.config

 <system.webServer>
 <httpProtocol>
      <customHeaders>
        <remove name="X-Powered-By" />
        <add name="Access-Control-Allow-Origin" value="*" />
        <add name="Access-Control-Allow-Headers" value="Accept, Content-Type, Origin" />
        <add name="Access-Control-Allow-Methods" value="GET, PUT, POST, DELETE, OPTIONS" />
      </customHeaders>
    </httpProtocol>
    <security>
      <requestFiltering>
        <requestLimits maxAllowedContentLength="1073741824" />
      </requestFiltering>
    </security>
    <modules>
      <remove name="FormsAuthentication" />
    </modules>
    <handlers>
      <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
      <remove name="OPTIONSVerbHandler" />
      <remove name="TRACEVerbHandler" />
      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
    </handlers>
  </system.webServer>

Answer 1

这对我有用：

var settings = {
  "async": false,
  "url": url,
  "dataType": "json",
}

$.ajax(settings).done(function(response) {
  $.each(JSON.parse(response), function(index, item) {

  })
});