Javascript笔记-跨域xmlhttpRequest跨域Cors

        function createCORSRequest(method, url) {
  var xhr = new XMLHttpRequest();
  if ("withCredentials" in xhr) {
    // XHR for Chrome/Firefox/Opera/Safari.
    xhr.open(method, url, true);
  } else if (typeof XDomainRequest != "undefined") {
    // XDomainRequest for IE.
    xhr = new XDomainRequest();
    xhr.open(method, url);
  } else {
    // CORS not supported.
    xhr = null;
  }
  return xhr;
}

        var req = new createCORSRequest(‘GET‘, ‘https://xunchayun.oss-cn-beijing.aliyuncs.com/3dImage/20190715/9058134a-d375-4f36-8192-906c02576848.jpg‘);
        //xhr.withCredentials = false;
        //xhr.open(‘GET‘, ‘https://xunchayun.oss-cn-beijing.aliyuncs.com/3dImage/20190715/9058134a-d375-4f36-8192-906c02576848.jpg‘, true);
        //xhr.setRequestHeader(‘Access-Control-Allow-Origin‘, ‘*‘);
        //xhr.setRequestHeader("X-Requested-With","XMLHttpRequest");
        //xhr.setRequestHeader(‘Access-Control-Allow-Credentials‘, ‘true‘);
        //xhr.setRequestHeader("Accept","*/*");
        //xhr.setRequestHeader(‘Access-Control-Allow-Methods‘,‘POST, GET, OPTIONS‘);
        //xhr.setRequestHeader(‘Content-Type‘, ‘image/jpeg‘);
        req.send();