var checked = false; 
   var Sizes = document.BuyProduct.Sizes;

   if(typeof(Sizes[0].checked)=="undefined") {
      Sizes[0] = Sizes;
   }

   if (Sizes.length){
      for (var i=0; i<Sizes.length; i++)  
      {  
         if (Sizes[i].checked) {  
         checked = true;   
         }  
      }
   }
   else if(Sizes.checked)
   {
      checked=true;
   }
 
   if(!checked) 
   {  
      Errors++
      document.getElementById('mySpan1a').style.display='block';
      document.getElementById('mySpan1a').innerHTML='Please Select a Size!';
      document.getElementById('mySpan1b').style.display='inline';
      document.getElementById('mySpan1b').innerHTML='! ';
   }
   else
   {
      document.getElementById('mySpan1a').style.display='none';
      document.getElementById('mySpan1a').innerHTML='';
      document.getElementById('mySpan1b').style.display='none';
      document.getElementById('mySpan1b').innerHTML='';
   }