[javascript] Easiest way to open a download window without navigating away from the page

Put this in the HTML head section, setting the url var to the URL of the file to be downloaded:

<script type="text/javascript">  
function startDownload()  
{  
     var url='http://server/folder/file.ext';    
     window.open(url, 'Download');  
}  
</script>

Then put this in the body, which will start the download automatically after 5 seconds:

<script type="text/javascript">  
setTimeout('startDownload()', 5000); //starts download after 5 seconds  
</script> 

(From here.)