How to get numeric value from a prompt box? [duplicate]

Question

I was trying to do some simple mathematical calculations in HTML and jQuery and JavaScript, so I wanted to get input from user.
For input I tried doing this :

 var x = prompt("Enter a Value","0");
 var y = prompt("Enter a Value", "0");

But I am not able to perform any kind of calculations as these values are strings.
Please, can any one show me how to convert them into integers.

Answer 1

parseInt() or parseFloat() are functions in JavaScript which can help you convert the values into integers or floats respectively.

Syntax:

 parseInt(string, radix);
 parseFloat(string); 

• string: the string expression to be parsed as a number.
  
• radix: (optional, but highly encouraged) the base of the numeral system to be used - a number between 2 and 36.

Example:

 var x = prompt("Enter a Value", "0");
 var y = prompt("Enter a Value", "0");
 var num1 = parseInt(x);
 var num2 = parseInt(y);

After this you can perform which ever calculations you want on them.

Answer 2

JavaScript will "convert" numeric string to integer, if you perform calculations on it (as JS is weakly typed). But you can convert it yourself using parseInt or parseFloat.

Just remember to put radix in parseInt!

In case of integer inputs:

var x = parseInt(prompt("Enter a Value", "0"), 10);
var y = parseInt(prompt("Enter a Value", "0"), 10);

In case of float:

var x = parseFloat(prompt("Enter a Value", "0"));
var y = parseFloat(prompt("Enter a Value", "0"));