title: Javascript Authorization HTTP Headers
body: <p>I am currently trying to set up a POST request to an REST API (Cloudsight) with basic authorization. My code so far is: </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>var xhr = new XMLHttpRequest();
  
  xhr.open("POST", "http://api.cloudsightapi.com/image_requests", true);
  xhr.setRequestHeader("Authorization:", "CloudSight [key]");
  xhr.setRequestHeader("Content-Type", "http://previews.123rf.com/images/valzann/valzann1412/valzann141200061/34262193-cigarette-end-on-a-white-background-Stock-Photo.jpg");
  
  xhr.send(null);
  console.log(xhr.status);
  console.log(xhr.statusText);</code></pre>
  </div>
  </div>
  </p>
  
  <p>When I try and run it I get the error: Uncaught SyntaxError: Failed to execute 'setRequestHeader' on 'XMLHttpRequest': 'Authorization:' is not a valid HTTP header field name.</p>
  
  <p>Does anyone know what is wrong with the code? I am very new to Javascript and APIs but would very much appreciate an answer. (Here's the link to Cloudsight's documentation if it helps: <a href="https://cloudsight.readme.io" rel="nofollow">https://cloudsight.readme.io</a> I have looked through it and tried to find other Authorization HTTP Header Javascript examples without success.)</p>