Using the document object to explain objects.
The column on the left are properties of the document object. They are static attributes of the object. Lets say you want to write out the date and time of the last modification to your page onto the screen. Here's what you would do:
Whenever you update your page and save it, this script will display the date and time of this occurrence. Something you can add to the end of your page right now! In this example, "document.lastModified" is a property of "document" Its a static attribute of the current document. In order to show this property, we used the non-static method to write this information out. Notice that we used "+" to put together "This page was last modified:" and example. The "+" sign is used to "combine" strings into one-similar to math, in a sense.
Lets try playing around with another document method then. Looking at the above chart, lets use "referrer", which gives the URL of the page that you came from to get here. Lets see what this might be useful for:
<script> document.writeln("Please thank this site for adding a link to me!") document.write(document.referrer) </script>
Ok, maybe not so useful like this, but you get the point.