title: Create a download link from a Blob URL
body: <p>In a Google chrome extension I am working on, a file is downloaded from a server with an <code>XMLHttpRequest</code>. This file contains some binary data which are stored in an <code>ArrayBuffer</code> object. In order to provide the possibility to download this file I am using the <code>createObjectURL</code> API.</p>
  
  <pre><code>function publish(data) {
    if (!window.BlobBuilder &amp;&amp; window.WebKitBlobBuilder) {
      window.BlobBuilder = window.WebKitBlobBuilder;
    }
    var builder = new BlobBuilder();
    builder.append(data);
    var blob = builder.getBlob();
    var url = window.webkitURL.createObjectURL(blob);
    $("#output").append($("&lt;a/&gt;").attr({href: url}).append("Download"));
  </code></pre>
  
  <p>}</p>
  
  <p>It is working fine; except that the filename is an opaque UUID like <code>9a8f6a0f-dd0c-4715-85dc-7379db9ce142</code>. Is there any way to force this filename to something more user-friendly?</p>