November 2001
Intermediate to advanced
936 pages
68h 43m
English
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Name
parseFloat( ) — convert a string to a number
Availability
JavaScript 1.0; JScript 1.0; ECMAScript v1
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
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( ).
Bugs
NaN is not supported in JavaScript 1.0, so in that
version of the language, parseFloat( ) returns 0
when it cannot parse s. This means that in
JavaScript 1.0, if the return value of parseFloat( ) is 0, you must perform additional tests on
s to determine whether it really
represents the number zero or does not represent a number at all.
See Also
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.