User Guide

Using Flash MX 2004 to create content for Flash Player 4 321
In Flash 4 ActionScript, these operators were always numeric operators. In Flash 5 and later,
they behave differently, depending on the data types of the operands. To prevent any semantic
differences in imported files, the
Number() function is inserted around all operands to these
operators. (Constant numbers are already obvious numbers, so they are not enclosed
in
Number()). For more information on these operators, see the operator table in “Operator
precedence and associativity” on page 49 and “Deprecated Flash 4 operators” on page 311.
• In Flash 4, the escape sequence \n generated a carriage return character (ASCII 13). In Flash 5
and later, to comply with the ECMA-262 standard,
\n generates a line-feed character (ASCII
10). An
\n sequence in Flash 4 FLA files is automatically converted to \r.
• The & operator in Flash 4 was used for string addition. In Flash 5 and later, & is the bitwise
AND operator. The string addition operator is now called
add. Any & operators in Flash 4 files
are automatically converted to
add operators.
• Many functions in Flash 4 did not require closing parens; for example, Get Timer, Set
Variable
, Stop, and Play. To create consistent syntax, the getTimer function and all actions
now require parentheses [()]. These parentheses are automatically added during the conversion.
• In Flash 5 and later, when the getProperty function is executed on a movie clip that doesn’t
exist, it returns the value
undefined, not 0. The statement undefined == 0 is false in
ActionScript after Flash 4 (in Flash 4,
undefined == 1). In Flash 5 and later, solve this
problem when converting Flash 4 files by introducing
Number() functions in equality
comparisons. In the following example,
Number() forces undefined to be converted to 0 so
the comparison will succeed:
getProperty("clip", _width) == 0
Number(getProperty("clip", _width)) == Number(0)
Note: If you used any Flash 5 or later keywords as variable names in your Flash 4 ActionScript, the
syntax returns an error when you compile it in Flash MX 2004. To solve this problem, rename your
variables in all locations. For information, see “Keywords and reserved words” on page 32 and
“Naming a variable” on page 44.
Using slash syntax
Slash syntax (
/) was used in Flash 3 and 4 to indicate the target path of a movie clip or variable. In
slash syntax, slashes are used instead of dots and variables are preceded with a colon, as shown in
the following example:
myMovieClip/childMovieClip:myVariable
To write the same target path in dot syntax (see “Dot syntax” on page 29), which is supported by
Flash Player 5 and later, use the following syntax:
myMovieClip.childMovieClip.myVariable
Slash syntax was most commonly used with the tellTarget action, but its use is also no longer
recommended. The
with action is now preferred because it is more compatible with dot syntax.
For more information, see
tellTarget and with in Flash ActionScript Language Reference.