Imbedding iMovie video Question

[Fender2112]

I used iMove to create a video. Then used iWeb to create a web page with the video. Then publish the web site. However, Safari and Firefox do not recognize the video.

When I create the video, I use the "Share" function to export the video as .m4v (H.264).
Then in iWeb, I drag the video from the media browsers to the web page and publish it.

Is there something I am missing?

Thanks