December 26, 1999 - Sharing Behaviors | WebReference

December 26, 1999 - Sharing Behaviors

Yehuda Shiran December 26, 1999
Sharing Behaviors
Tips: December 1999

Yehuda Shiran, Ph.D.
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We have shown in previous tips (December 24, 1999, December 23, 1999, and December 25, 1999) how to define a Behavior and associate it with one DHTML element. But the real power of Behaviors is that a single Behavior can be shared by several DHTML elements. By assigning different values to the scriptlet's properties, slightly different behaviors can be achieved. Here is our single Blinking Soccer from Column 22, DHTML Behaviors:

<DIV CLASS="soccer" x="200" y="250" onFifthBlink = "alert('Fifth Blink Point')"><IMG SRC="soccer.gif"></DIV>

Now, let's add five more soccer balls, in different window's locations. The DIV line stays the same, except that the x and y attributes on each DIV are assigned different values:

<DIV CLASS="soccer" x="50" y="100" onFifthBlink = "alert('Fifth Blink Point')"><IMG SRC="soccer.gif"></DIV>
<DIV CLASS="soccer" x="100" y="150" onFifthBlink = "alert('Fifth Blink Point')"><IMG SRC="soccer.gif"></DIV>
<DIV CLASS="soccer" x="150" y="200" onFifthBlink = "alert('Fifth Blink Point')"><IMG SRC="soccer.gif"></DIV>
<DIV CLASS="soccer" x="200" y="250" onFifthBlink = "alert('Fifth Blink Point')"><IMG SRC="soccer.gif"></DIV>
<DIV CLASS="soccer" x="250" y="300" onFifthBlink = "alert('Fifth Blink Point')"><IMG SRC="soccer.gif"></DIV>

Sharing a single module by several elements is one of the cornerstones of any object-oriented languages. It is more than calling a procedure with different arguments. Object-oriented modules encapsulate both data and methods that can operate on this data. Behaviors are exactly that.