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:
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.
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