Webconfig配置：

1、

Ajax跨域调用webService_Ajax

<webServices>
      <protocols>
        <add name="HttpSoap"/>
        <add name="HttpPost"/>
        <add name="HttpGet"/>
        <add name="Documentation"/>
      </protocols>
</webServices>

2、

Ajax跨域调用webService_Ajax_02

<httpProtocol>
      <customHeaders>
        <add name="Access-Control-Allow-Methods" value="OPTIONS,POST,GET"/>
        <add name="Access-Control-Allow-Headers" value="x-requested-with,content-type"/>
        <add name="Access-Control-Allow-Origin" value="*" />
      </customHeaders>
</httpProtocol>

3、取消注释，

Ajax跨域调用webService_Ajax_03