function attachEvents(){
	var oQuantity=document.getElementById('quantity');
	if(oQuantity){
		oQuantity.onchange=function(){calculatePrice();};
	}	
	//allows visible pre-filling of delivery address if javascript supported
	var d=document.getElementById('dsame');
	if(d){
		d.onclick=function(){addressFiller(this);};
	}
}


//this is outside all functions
if(document.getElementById){
	window.onload=attachEvents;
}

function validate(frm){
	//all-purpose form validation function
	//give form elements class="validate" to perform validation
	//could be enhanced to display label text instead of form name, perhaps?
	//would need to get reference to label first, then form
	//for the moment, name form elements as you would like them to be displayed, but with underscore, e.g. full_name
	//does this element need validating?
	for(i=0;i<frm.elements.length;i++){
		el=frm.elements[i];
		str=el.value;
		strDisplayName=el.name.replace('_',' ')
		aryV=el.className.split('_');
		if(aryV[0]=='validate'){
			//first, check presence
			if(str.length<1){
				alert('Please provide ' + strDisplayName);
					  //name.replace('_',' '));
				return false;
			}else{
				switch(aryV[1]){
					case 'number':
						//spaces, brackets,+ and  - are allowed
						re=/[\s()+-]/g;
						str=el.value.replace(re,'');
						re=/^\d+$/;
					break;
					case 'email':
						//nothing fancy, just checks for presence of @ and . with at least one character between each
						//1@2.3 is valid, for example
						re=/.+@.+\..+/gi;
					break;
					default:
						re='';
					break;
				}
				if(re!=''){
					if(str.search(re)==-1){
						alert('Please provide a valid ' + strDisplayName);
						return false;
					}	
				}
			}
		}	
	}
	return true;
}

function addressFiller(chk){
	//allows visible pre-filling of delivery address if javascript supported
	var d=document.getElementById('dsame');
	fill=false;
	aryNames=new Array('name','address','postcode','tel');
	if(chk.checked){
		fill=true;
	}
		//fill boxes with values
		newValue=' ';
		for(i=0;i<aryNames.length;i++){
			if(fill){
				newValue=document.getElementById(aryNames[i]).value;
			}
			document.getElementById('d'+aryNames[i]).value=newValue;
		}
}

function MM_findObj(n, d) { //v4.01
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}

function MM_validateForm() { //v4.0
  var i,p,q,nm,test,num,min,max,errors='',args=MM_validateForm.arguments;
  for (i=0; i<(args.length-2); i+=3) { test=args[i+2]; val=MM_findObj(args[i]);
    if (val) { nm=val.name; if ((val=val.value)!="") {
      if (test.indexOf('isEmail')!=-1) { p=val.indexOf('@');
        if (p<1 || p==(val.length-1)) errors+='- '+nm+' must contain an e-mail address.\n';
      } else if (test!='R') { num = parseFloat(val);
        if (isNaN(val)) errors+='- '+nm+' must contain a number.\n';
        if (test.indexOf('inRange') != -1) { p=test.indexOf(':');
          min=test.substring(8,p); max=test.substring(p+1);
          if (num<min || max<num) errors+='- '+nm+' must contain a number between '+min+' and '+max+'.\n';
    } } } else if (test.charAt(0) == 'R') errors += '- '+nm+' is required.\n'; }
  } if (errors) alert('The following error(s) occurred:\n'+errors);
  document.MM_returnValue = (errors == '');
}

// Set delivery details fields same as billing details fields
function setDeliveryDetails() {
	if (document.getElementById('deliverySame').checked) {
		document.getElementById('deliveryFirstnames').value = document.getElementById('billingFirstnames').value;
		document.getElementById('deliverySurname').value = document.getElementById('billingSurname').value;
		document.getElementById('deliveryAddress1').value = document.getElementById('billingAddress1').value;
		document.getElementById('deliveryAddress2').value = document.getElementById('billingAddress2').value;
		document.getElementById('deliveryCity').value = document.getElementById('billingCity').value;
		document.getElementById('deliveryPostCode').value = document.getElementById('billingPostCode').value;
		document.getElementById('deliveryPhone').value = document.getElementById('billingPhone').value;
	}
}