parseFloat function
The parseFloat function
converts a string to a floating
point number. This is necessary
for values like '12.5px'
- when the first there is a number,
and then units of measurement. If
you apply the parseFloat
function to '12.5px', the
result will be the number 12.5
(and it will really be a number, not
a string). The conversion will only
occur if the integer is at the
beginning of the string, otherwise
NaN
will be displayed. You can set a
number system of a number as a
second optional parameter, and
the function will return the
number converted from the specified
number system to decimal.
Syntax
parseFloat(string, [number system]);
Example
Let's extract a fractional number from the beginning of a string:
console.log(parseFloat('10.3px'));
The code execution result:
10.3
Example
In this example, the function will not
be able to read the number (because it
is not at the beginning of the string)
and will return
NaN:
let str = 'width: 100px';
console.log(parseFloat(str));
The code execution result:
NaN