is their somethign wrong with this code ?

Number.prototype.formatMoney = function(c, d, t){
var n = this, c = isNaN(c = Math.abs(c)) ? 2 : c, d = d == undefined ? "," : d, t = t == undefined ? "." : t, s = n < 0 ? "-" : "", i = parseInt(n = Math.abs(+n || 0).toFixed(c)) + "", j = (j = i.length) > 3 ? j % 3 : 0;
   return s + (j ? i.substr(0, j) + t : "") + i.substr(j).replace(/(\d{3})(?=\d)/g, "$1" + t) + (c ? d + Math.abs(n - i).toFixed(c).slice(2) : "");
 }

Code (markup):

This code is suppose to format numbers to currency on keystroke.

However, the function does not work in ie8. it only works in ie8 compatibility mode.

Is their something wrong with it, to make it work in ie8 ?

 

this is from :

http://javascript.internet.com/forms/auto-currency.html

thanks in advance for any help