JavaScript: The Definitive Guide, 6th Edition

Name

parseFloat() — convert a string to a number

Synopsis

parseFloat(s)

Arguments

s

The string to be parsed and converted to a number.

Returns

The parsed number, or NaN if s does not begin with a valid number. In JavaScript 1.0, parseFloat() returns 0 instead of NaN when s cannot be parsed as a number.

Description

parseFloat() parses and returns the first number that occurs in s. Parsing stops, and the value is returned, when parseFloat() encounters a character in s that is not a valid part of the number. If s does not begin with a number that parseFloat() can parse, the function returns the not-a-number value NaN. Test for this return value with the isNaN() function. If you want to parse only the integer portion of a number, use parseInt() instead of parseFloat().

See Also

isNaN(), parseInt()