OAuth Authentication - 使用JavaScript访问令牌（CORS策略）错误

	 var key;  
	 var request = new XMLHttpRequest(); 
    request.open("POST", "https://login.microsoftonline.com/<<tenant_id>>/oauth2/token", true); 
  
	request.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
	request.setRequestHeader('Access-Control-Allow-Headers', 'x-requested-with');
	request.setRequestHeader('Access-Control-Allow-Origin', '*');
    request.send("grant_type=client_credentials&client_id=<<clientid>>&client_secret=<<clientsecret>>&resource:<<resourceurl>>"); // specify the credentials to receive the token on request
    request.onreadystatechange = function () {
        if (request.readyState == request.DONE) {
            var response = request.responseText;
            var obj = JSON.parse(response); 
            key = obj.access_token; 
            token_ = key; 
        }
    }