API : https://api.weixin.qq.com/wxa/servicemarket?access_token params = {       "service": "wx79ac3de8be320b71",       "api": "OcrAllInOne",       "data": {         "img_data": "",         "data_type": 2,         "ocr_type": 1       },       "client_msg_id": "id123"     };     $.ajax({       type: "POST",       url: "https://api.weixin.qq.com/wxa/servicemarket?access_token=token",       contentType: "application/json",       data: JSON.stringify(params),  //此处注意，要转换成JSON.stringify(对象)       dataType: "json",       success: function (data) {       },       error: function (data) {       }     });