Autoplaying a <video> element using javascript

I have a few elements set up in my html with the autoplay option included. I have found that Chrome doesn't seem particularly willing to autoplay these videos for whatever reason. I'd like to add a bit of javascript to set the video to play once it's loaded. I understand I need to use the play() method on the DOM element in question.

I'm using:

  document.getElements开发者_运维知识库ByTagName('video').play();

This code successfully autoplays my video elements. However, it also throws an error picked up in the console as

Uncaught TypeError: Object #< NodeList > has no method 'play'

I haven't come across this error before and it's stopping the rest of my javascript for executing properly. Any ideas as to what this is and how to resolve it?

Thanks!

That's because getElementsByTagName returns an array of elements so you may specify which element in this array you want.

 document.getElementsByTagName('video')[0].play();

Maybe affecting an id to the <video> element may be better, you can then retreive it by using getElementById(id).