Download file using ajax GET request with authorization header

 <td><button onclick="downloadContacts()">Click to Download</button>

function downloadContacts() {
    console.log(userId);
    geturl = 'get-url-of-file'+ userId;
     var req = new XMLHttpRequest();
     req.open("GET", geturl, true);
     req.responseType = "blob";
     req.setRequestHeader('Authorization', authorizationToken);
     req.onload = function (event) {
         var blob = req.response;
         var fileName = 'contact.csv';
         var link=document.createElement('a');
         link.href=window.URL.createObjectURL(blob);
         link.download=fileName;
         link.click();
     };

     req.send();
 }