javascript window.open() to a html file opens the browser download dialog
<p>I'm creating a print (preview)window, for which I want to load the core html from the site assets:</p>

<p>The code:</p>

<pre><code>window.open('/SiteAssets/reportingPrintBase.html','_blank','width=1250,height=800,menubar=yes,scrollbars=yes,resizable=yes');   
</code></pre>

<p>The html: </p>

<pre><code>&lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"&gt;
&lt;html xmlns:o="urn:schemas-microsoft-com:office:office" lang="en-us" dir="ltr"&gt;
&lt;head&gt;
&lt;meta http-equiv="Content-Type" content="text/html; charset=utf-8" /&gt;
&lt;meta http-equiv="Expires" content="0" /&gt;
&lt;link rel="stylesheet" type="text/css" href="/SiteAssets/reporting.css" /&gt;
&lt;title&gt;Untitled 1&lt;/title&gt;
&lt;/head&gt;
&lt;body&gt;
&lt;div id="printHeader"&gt;Reporting&lt;/div&gt;
&lt;div id="printBody"&gt;&lt;/div&gt;
&lt;div id="printFooter"&gt;Reporting Footer&lt;/div&gt;
&lt;/body&gt;
&lt;/html&gt;
</code></pre>

<p>The popup opens, but I'm then asked if want to download the file. This doesn't happen in a normal asp.net env. So I'm assuming it has something to do whith the way sharepoint sets headers.. </p>

<p>So how can I get the popup window to simply render the html?</p>
