* 3 new
** Window.location
   Can find information about window's current URL, for example,
   window.location.hostname will be the URL's hostname.
** HTML pauses loading while fetching javascript
   Developers tend to load external JavaScript files at the end of the html
   in an attempt to avoid pausing the loading of HTML
** Async and defer attributes
   Able to load web page concurrently with loading and processing
   JavaScript with async attribute.

   Defer allows it all to load together, but waits until the end to
   process the JavaScript
* 2 interesting
** Web pages written before defer and async attributes
   Many web pages could load faster if they implemented these attributes
** Javascirpt minification
   Javascript can be minified in order to lower the size of the file.
   The interesting bit, is that it can do things like replacing long
   variable names with short ones.
* 1 unclear
  One little thing about APIs. Are they just public functions? I imagine them as either public functions that are used directly (like a library), or public functions that are activated by sending messages from one program to another.