The src of iframe is a URL to a video. Every time when the page is loaded, it asked me whether to save or open the video. But the video show well on firefox and chrome. When the URL points to video on youtube, it works too. Anyone has the same problem? My IE is 11. But it should work on most IE versions.
<iframe width="550" height="400" src="http://techslides.com/demos/sample-videos/small.mp4" frameborder="0"></iframe>