HTML Goodies: Script Tip: Week 2

     In this tip we'll quickly discuss the use of those objects in what I call a hierarchy statement. Here's a very bare-bones image flip script:

<A HREF="http://www.cnn.com" onMouseOver="document.pic1.src='menu1on.gif'" onMouseOut="document.pic1.src='menu1off.gif'"> <IMG SRC="menu1off.gif" BORDER=0 NAME="pic1"></a>

     We'll actually use this script for this and the next Script Tip. The portion of this script I am interested in most is this one "document.pic1.src='menu1on.gif".

     Remember from the last tip that document is an object? Well, it is. Here we're using the document object to set up a hierarchy statement. Hierarchy statements are listings of elements under a specific object. This statement, for instance, is under the object document--the HTML document.
     Always in these statements, it's biggest to smallest in stature reading left to right. So in this case, the statement is saying:

• The document...
• that contains something called pic1...
• receives this source (denoted by src)...
• an image called menu1on.gif.

     Notice it's always a dot (.) that separates the items in the hierarchy statements. I should say here that the pic1 item is the name of the image command. See that in the full code above?

     So now you have a general idea of what is happening when you see long lists of elements in JavaScripts. You're seeing a hierarchy statement denoting a specific portion of an object.