Do HTML5 videos keep computer on?

Question

This might sound a little odd, but I was curious if HTML5 <video> tags are meant to keep your computer "awake" or prevent it from turning off somehow way while playing. I know that would be the expected behaviour considering it's a video and you wouldn't want your screen to turn off, but upon Googling it most of the results ended up being people seeking to try and keep the screen on, which leads me to believe that by default it doesn't. I only started exploring this because I've noticed when leaving my page open, the computer does in fact stay awake.

This is how I've implemented the video:

<video autoplay="autoplay" class="header-video" id="header-video" loop="loop" muted="muted" preload="preload">
    <source src="video.mp4" type="video/mp4"></source>
    <source src="video.webm" type="video/webm"></source>
 </video>

And I've noticed this happening on my iMac in Chrome.

Edit

Below are my power settings - note that this is default from a fresh install of Mavericks. I guess I'm curious because I'd like to know if, by default, people should be aware about whether or not their computer will stay awake. It could be a pretty big issue in terms of energy consumption.

Answer 1

I think this is default behavior from the operating system for videos. I was reviewing some power options and sleep options and apple specifically noted that the options are changed during videos and dvds so that it doesnt sleep. Check it out Apple Support - Mac not sleeping during video