Javascript API Call JIRA Cloud Basic Auth does not work and receiving Access-Control-Allow-Origin-CodePudding

I have a question reagrding how to call make a API call for JIRA Cloud API using Basic Authorization. I want to get my Issues and then edit some values through REST API.

I follow some tutorials and examples

https://developer.atlassian.com/cloud/jira/platform/rest/v3/intro/

I took a look in https://support.atlassian.com/user-management/docs/create-and-update-groups/

I think I must give premissions in the as I read here https://developer.atlassian.com/cloud/jira/platform/oauth-2-3lo-apps/

and for the basic authorization I shall get a api token here use the https://developer.atlassian.com/cloud/jira/platform/basic-auth-for-rest-apis/

I use this code:

<html>
<head>
</head>
<body>
<script>
console.log("called function httpGetRequest");  
        
    
    let url = 'https://my-domain.atlassian.net/rest/api/3/issue/TEST-2';
    let user = '<my email address>';
    let password = '<basic api token>';
    let pass_base64 = btoa(password);

    let auth_buff = user ":" password;
    let auth = btoa(auth_buff);
    

  
    console.log ("auth : " auth);

    
    var xhr = new XMLHttpRequest();

 
    xhr.open("GET", url);
    xhr.withCredentials = true;
    


    
    xhr.setRequestHeader("Authorization", "Basic "   auth);
    xhr.setRequestHeader('Accept', 'application/json');


    xhr.onreadystatechange = function () {
        console.log( 'Response: '  xhr.status   ' -  ' xhr.responseText);
       if (xhr.readyState === 4) {
          console.log(xhr.status);
          console.log(xhr.responseText);
       }};



</script>
</body>
</html>

I get always the error:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://my-domain.atlassian.net/rest/api/3/issue/TEST-2. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing).

XHR GET https://my-domain.atlassian.net/rest/api/3/issue/TEST-2.

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://my-domain.atlassian.net/rest/api/3/issue/TEST-2. . (Reason: CORS request did not succeed).

What I am doing wrong?

CodePudding user response：

I create the request in a plain js request.js and then with "node request.js" I get a response properly. With a script definition in the html was not possible.