i would like to now if there is a way to convert string (like 132) into a number USING javascript.

Use the .net feature Parse:

var s = "1234";
var i = int.Parse(s);

`parseInt` does the same thing:

var s = "1234";
var i = parseInt(s);

If there's any chance the string contains non-numeric characters, use TryParse:

var s = "1234";
var i : int;
if (int.TryParse(s, i)) print ("Succeeded, and the result is " + i);