The Essential Guide to HTML5

CANNONBALL AND SL INGSHOT

Function Invoked By / Called By Calls

change Invoked by action of the setInterval function
called in finish

drawall, calls the moveit method of

cball, which is moveball.

Ball Invoked directly by code in a var statement

Myrectangle Invoked directly by code in a var statement

drawball Invoked by call of the draw method for the one
Ball object

drawrects Invoked by call of the draw method for the
target object

moveball Invoked by call of the moveit method for the
one Ball object

Picture Invoked directly by code in var statements

drawAnImage Invoked by call of the draw method for a
picture object

Sling Invoked directly by code in var statements

drawsling Invoked by call of the draw method for mysling

Table 4-6 shows the code for the slingshot application, with the new or changed lines commented. Notice

that the form is absent from the body element. Before looking at the code, try to identify what parts will be

the same as in the cannonball application and what would be different.

Table 4-6. The Slingshot Application

Code Explanation