How to call rest api from javascript?

"Access to XMLHttpRequest at 'https://localhost:44300/api/sample?Empno=1234' from origin 'http://localhost' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: It does not have HTTP ok status."

<pre>Below the java script i used

 const formData = new FormData();
 const response = new XMLHttpRequest();
 response.open("GET", "https://localhost:44300/api/sample?Empno=1234");

response.setRequestHeader('key', '@1234');
response.send(formData);

response.onload = (e) => {
    alert(response.response);
}

And below the jquery

  alert('ajax');
     $.ajax({ 
         type: "GET",
         dataType: "json",
         beforeSend: function (request) {
             request.setRequestHeader('key', '@1234');
         },
         url: "https://localhost:44300/api/sample?Empno=1234",
         success: function(data){        
            alert(data);
         }
     });

In rest api web config i added this tag for enable cros policy

   <httpProtocol>
 <customHeaders>
    <add name="Access-Control-Allow-Origin" value="*" /> 
   </customHeaders>
 </httpProtocol>