JS_0029：JS用 XMLHttpRequest 发送http请求

1，

    httpPost(image) {
        return new Promise((resolve, reject) => {
            const http = new XMLHttpRequest();
            http.onload = () => {
                try {
                    const msg = JSON.parse(http.responseText);
                    if (http.status === 200) {
                        if (msg.statusCode === 0) {
                            resolve(msg.result);
                        }
                        else {
                            reject(msg);
                        }
                    }
                    else {
                        reject(msg);
                    }
                }
                catch (err) {
                    reject(err);
                }
            };
            http.onerror = (err) => {
                reject(err);
            };
            http.open('POST', this.recognizeUrl);
            http.setRequestHeader('Content-Type', 'application/json;Charset=UTF-8');
            if (this.token) {
                // 将云识别认证token写在请求头中
                http.setRequestHeader('Authorization', this.token);
            }
            http.send(JSON.stringify(image));
        });
    }