how to format string(numbers) printing in javascript

Question

For example. I want to print numbers from 1 to 20

but I want print 1 as 01 , 2 as 02 and so on ..

Answer 1

formatNumber = function( num )
{
  if ( num < 10 )
  {
    return "0" + num;
  }
  else
  {
    return "" + num;
  }
}