後端這裡是 .net framework4.6 webapi

在web.config中<system.webServer>節點配置

 <httpProtocol>
      <customHeaders>
        <add name="Access-Control-Allow-Origin" value="*" />
        <add name="Access-Control-Allow-Headers" value="Content-Type,authorization,x-ms-request-id,x-ms-request-root-id" />
        <add name="Access-Control-Allow-Methods" value="GET, POST, PUT, DELETE, OPTIONS" />
      </customHeaders>
    </httpProtocol>

將原來的handlers中東西替換掉

 <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>