<video id="myvideo">
<source src="https://stackoverflow.com/questions/5399412/path/to/movie.mp4" />
</video>
<p onclick="toggleControls();">Toggle</p>
<script>
var video = document.getElementById("myvideo");
function toggleControls() {
if (video.hasAttribute("controls")) {
video.removeAttribute("controls")
} else {
video.setAttribute("controls","controls")
}
}
</script>
See it working on jsFiddle: http://jsfiddle.net/dgLds/