User Guide

30 ActionScript language elements
true constant
A unique Boolean value that represents the opposite of false. When automatic data typing
converts
true to a number, it becomes 1; when it converts true to a string, it becomes
"true".
Availability: ActionScript 1.0; Flash Lite 1.1
Example
The following example shows the use of true in an if statement:
var shouldExecute:Boolean;
// ...
// code that sets shouldExecute to either true or false goes here
// shouldExecute is set to true for this example:
shouldExecute = true;
if (shouldExecute == true) {
trace("your statements here");
}
// true is also implied, so the if statement could also be written:
// if (shouldExecute) {
// trace("your statements here");
// }
The following example shows how automatic data typing converts true to the number 1:
var myNum:Number;
myNum = 1 + true;
trace(myNum); // output: 2
See also
false constant, Boolean
undefined constant
A special value, usually used to indicate that a variable has not yet been assigned a value. A
reference to an undefined value returns the special value
undefined. The ActionScript code
typeof(undefined) returns the string "undefined". The only value of type undefined is
undefined.
In files published for Flash Player 6 or earlier, the value of
String(undefined) is "" (an
empty string). In files published for Flash Player 7 or later, the value of
String(undefined)
is
"undefined" (undefined is converted to a string).