parseInt function
The parseInt function converts
a string to an integer. This is necessary
for values like '12px' - when
first there is a number, and then units
of measurement. If you apply the
parseInt function to '12px',
then the result will be the number 12
(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. As a second parameter,
you can specify a number system of a
number, and the function will return the
number converted from the specified number
system to decimal.
Syntax
parseInt(string, [number system]);
Example
Let's convert a string to an integer:
console.log(parseInt('10px'));
The code execution result:
10
Example
When converting a fraction, a fractional part will be discarded:
console.log(parseInt('10.3px'));
The code execution result:
10
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(parseInt(str));
The code execution result:
NaN
See also
-
the
parseFloatfunction
that extracts a fractional number from the beginning of a string -
the
Numberfunction
that converts to a number