String to Integer Conversion in JavaScript

JavaScriptWe have seen in previous tutorial that JavaScript treat a number as a string if you assign it using quotation marks.  Instead of addition of 2 numbers, it will perform concatenation.  To overcome this issue, we make use of parseInt() function in JavaScript.  This function will convert string to integer.  Example is given below.

Note:  If you try to retrieve a value within textbox using JavaScript, then that value will also be treated as a string.  So, you have to perform string to integer conversion to do calculation.

<title>JavaScript Tutorial </title>
<script type="text/javascript">

var n1 = "10";
var n2 = "30";

var total = n1+n2;
var sum = parseInt(n1) + parseInt(n2);

//Total = 1030

//Sum = 40