w3schools is not affiliated with the w3c and often has subtly incorrect information [See here](http://w3fools.com http://w3fools.com). My preferred resource on

w3schools is not affiliated with the w3c and often has subtly incorrect information [See here](http://w3fools.com http://w3fools.com). My preferred resource on the subject is the [Mozilla Developer Network](https://developer.mozilla.org/en-US/docs https://developer.mozilla.org/en-US/docs)