function pricePerPound() {
   var tables = document.getElementsByTagName('table');
   var tbody, thead,tcells, price,dir;
   var u = document.getElementById('unit-sel');
   for (var i=0;i<tables.length;i++) {
      tbody=tables[i].getElementsByTagName('tbody');
      tcells = tbody[0].getElementsByTagName('td');
      for (var j=0;j<tcells.length;j++) {
         if (tcells[j].className=='price') {
            price=tcells[j].innerHTML.replace(/[^\d\.]+/,'');
            if (/lb/.test(u.innerHTML)) {
               price = parseFloat(price*0.4538);
               price = toCurrency(price,2);
               dir=0;
            }
            else {
               price = tcells[j].title;
               dir=1;
            }            
            tcells[j].innerHTML='&pound;' + price;
         }
      }
      thead=tables[i].getElementsByTagName('thead');
      tcells = thead[0].getElementsByTagName('th');
      for (var j=0;j<tcells.length;j++) {
         if (tcells[j].className=='price') {
         if (dir==0) {
               tcells[j].innerHTML='Price per lb.';
            }
         else {
               tcells[j].innerHTML='Price per kg.';
            }
         }
      }
   }
   if (dir==0) {
         u.innerHTML = 'show in kilos';
   }
   else {
      u.innerHTML = 'show in lb';
   }
}

function toCurrency(num) {
	var result = Math.round(num*Math.pow(10,2))/Math.pow(10,2);
	if (/\.\d$/.test(result)) { result = result + '0'; }
	else if (/^\d$/.test(result)) { result = result + '.00'; }
	return result;
}