User Guide

|| (logical OR) 65
|| (logical OR)
Availability
Flash Player 4.
Usage
expression1 || expression2
Parameters
expression1, expression2
A Boolean value or an expression that converts to a Boolean
value.
Returns
A Boolean value.
Description
Operator (logical); evaluates expression1 (the expression on the left side of the operator) and
returns
true if the expression evaluates to true. If expression1 evaluates to false,
expression2 (the expression on the right side of the operator) is evaluated. If expression2
evaluates to
false, the final result is false; otherwise, it is true.
If you use a function call as
expression2, the function will not be executed by that call if
expression1 evaluates to true.
The result is
true if either or both expressions evaluate to true; the result is false only if both
expressions evaluate to
false. You can use the logical OR operator with any number of operands;
if any operand evaluates to
true, the result is true.
For more information, see “Operator precedence and associativity” in Using ActionScript in Flash.
Example
The following example uses the logical OR (||) operator in an if statement. The second
expression evaluates to
true, so the final result is true:
var x:Number = 10;
var y:Number = 250;
var start:Boolean = false;
if ((x>25) || (y>200) || (start)) {
trace("the logical OR test passed"); // output: the logical OR test passed
}
The message the logical OR test passed appears because one of the conditions in the if
statement is true (
y>200). Although the other two expressions evaluate to false, as long as one
condition evaluates to
true, the if block executes.
The following example demonstrates how using a function call as
expression2 can lead to
unexpected results. If the expression on the left of the operator evaluates to
true, that result is
returned without evaluating the expression on the right (the function
fx2() is not called).
function fx1():Boolean {
trace("fx1 called");
return true;