ActionScript for Flash MX: The Definitive Guide, Second Edition

parseInt() Global Function

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ActionScript Language Reference

Description

The parseFloat() function converts a string to a floating-point number (a number with a

fractional portion). It returns a useful value only for strings that contain a valid string repre-

sentation of a floating-point number; otherwise,

NaN is returned. The string must be of the

following form:

• A valid starting character. Valid characters are +, –, 0 through 9, e, E, and ., although

optional leading whitespace is acceptable (and ignored).

• Optional sign indicator (+ or –).

• At least one digit from 0–9 and an optional decimal point.

• Optional exponent starting with

e or E followed by integer exponent, which can itself

include an optional sign indicator (+ or –)—for example, “10e–3”.

Trailing characters that cannot be parsed as part of the preceding numeric format are

ignored but do not necessarily cause

NaN to be returned. The number derived from the

supplied string starts with the first nonblank character in the string and ends with the char-

acter before the first character that is not a legitimate character.

Usage

Because user-input data entered into text fields always belongs to the string datatype, we

often use parseFloat() to extract numeric data from user-supplied text. Note that

parseFloat() can extract