function MM_swapImgRestore() { //v3.0
  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

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_swapImage() { //v3.0
  var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
   if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}

function echeck(str) {

		var at="@"
		var dot="."
		var lat=str.indexOf(at)
		var lstr=str.length
		var ldot=str.indexOf(dot)
		if (str.indexOf(at)==-1){
		   return false
		}

		if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
		   return false
		}

		if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		    return false
		}

		 if (str.indexOf(at,(lat+1))!=-1){
		    return false
		 }

		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		    return false
		 }

		 if (str.indexOf(dot,(lat+2))==-1){
		    return false
		 }
		
		 if (str.indexOf(" ")!=-1){
		    return false
		 }

 		 return true					
	}

function check_form()
{
	var ok_to_send = true;
	
	with (document.forms.SagePayForm)
	{
		if (billingfirstnames.value == "")
		{
			alert("Please enter your first name.");
			billingfirstnames.focus();
			ok_to_send = false;
		}
		else if (billingsurname.value == "")
		{
			alert("Please enter your surname.");
			billingsurname.focus();
			ok_to_send = false;
		}
		else if (customeremail.value == "")
		{
			alert("Please enter your email address.");
			customeremail.focus();
			ok_to_send = false;
		}
		else if (echeck(customeremail.value)==false)
		{
			alert("Please enter a valid email address.");
			customeremail.focus()
			ok_to_send = false;
		}
		else if (billingaddress1.value == "")
		{
			alert("Please enter your address.");
			billingaddress1.focus();
			ok_to_send = false;
		}
		else if (billingpostcode.value == "")
		{
			alert("Please enter your postcode.");
			billingpostcode.focus();
			ok_to_send = false;
		}
		
		if (ok_to_send)
		{
			return true;
		}
		else
		{
			return false;
		}
	}
}