Add decimal to last two numbers in numeric string

Question

I have the following numeric string where I need to add a decimal to the last two numbers.

So

300000

Becomes

3000.00

Can someone please help me out here, which regex code should I use for this? Or should I not use regex at all for this.

Thanks

Answer 1

var str="300000";

var resStr=str.substring(0,str.length-2)+"."+str.substring(str.length-2);

document.write(resStr);