Use the oncanplaythrough event to completely preload video. You can try to run the following code.
Example
<!DOCTYPE html>
<html>
<body>
<video id="myVideo" width="400" height="200" controls oncanplaythrough="display()">
<source src="/html5/foo.ogg" type="video/ogg" />
<source src="/html5/foo.mp4" type="video/mp4" />
Your browser does not support the video element.
</video>
<script>
function display() {
alert("Can be played without pausing for buffering.");
}
</script>
</body>
</html>