The parseInt function in JavaScript is utilized to analyze a given string and transform it into an integer value. When passing a string as an argument, there is also the option to include a radix argument, which allows us to define the numeral system that should be applied.
Syntax
The syntax for the parseInt function is expressed as follows:
Number.parseInt(string, radix)
Parameter
string - It represents the string to be parsed.
radix - This parameter is optional. It is an integer value ranging from 2 to 36 that signifies the numeral system that will be utilized.
Return
An integer value. It produces NaN if the initial character is not convertible into a numerical format.
JavaScript Number parseInt method example
In this section, we will explore the parseInt function using a range of examples.
Example 1
Let's see a simple example of parseInt method.
<script>
var a="50";
var b="50.25"
var c="String";
var d="50String";
var e="50.25String"
document.writeln(Number.parseInt(a)+"<br>");
document.writeln(Number.parseInt(b)+"<br>");
document.writeln(Number.parseInt(c)+"<br>");
document.writeln(Number.parseInt(d)+"<br>");
document.writeln(Number.parseInt(e));
</script>
Output:
50
50
NaN
50
50
Example 2
Let's examine an illustration of how to concatenate two strings, both by utilizing the parseInt method and by not using it.
<script>
var a="10";
var b="20";
var c=a+b;
document.writeln("Before invoking parseInt(): "+c+"<br>");
var c=Number.parseInt(a)+Number.parseInt(b);
document.writeln("After invoking parseInt(): "+c);
</script>
Output:
Before invoking parseInt(): 1020
After invoking parseInt(): 30
Example 3
In this illustration, we will provide the radix parameter to the parseInt function.
<script>
var a="50";
document.writeln(Number.parseInt(a,10)+"<br>");
document.writeln(Number.parseInt(a,8)+"<br>");
document.writeln(Number.parseInt(a,16));
</script>
Output:
50
40
80
