MACROMEDIA FLASH MX 2004 - ACTIONSCRIPT Reference Manual page 259

-= (subtraction assignment)
Availability
Flash Player 4.
Usage
expression1 -= expression2
Parameters
expression1,expression2
Returns
Nothing.
Description
Operator (arithmetic compound assignment); assigns
. For example, the following two statements are the same:
expression2
x -= y;
x = x - y;
String expressions must be converted to numbers; otherwise,
Example
Usage 1: The following example uses the
to the variable .
x
x = 5;
y = 10;
x -= y
trace(x);
//returns -5
Usage 2: The following example shows how strings are converted to numbers.
x = "5";
y = "10";
x -= y;
trace(x);
// returns -5
A number or expression that evaluates to a number.
operator to subtract 10 from 5 and assign the result
-=
the value of
expression1
is returned.
NaN
-= (subtraction assignment)
expression1 -
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