// Convert string to number
function strToNumber(value)
{
	return parseFloat(value);
}


// Convert number to pixel
function numberToPixel(value)
{
	return value+"px";
}


function isPixel(value)
{
  var value1 = strToNumber(value);
  if(isNaN(value1))
  {
    value1 = null;
  }
  var value2 = numberToPixel(value1);
  return (value2 == value);
}