function calSubtotal() {
   var quantity = document.getElementById('quantity').value;
   
   if(!isNaN(quantity)) {
   
		   //become a integer
		   quantity = Math.round(quantity);
		   document.getElementById('quantity').value = quantity;
		   
		   //check lower range
		   if (quantity < 5) {
		      document.getElementById('quantity_alert').innerHTML = "<font size=1 color=red>Min. quantity is 5</>";  
		      document.getElementById('quantity').value = "5";  
		      quantity = 5;  
		   }
		   
		   //check upper range
		   else if (quantity > 1000000) {
		   		document.getElementById('quantity_alert').innerHTML = "<font size=1 color=red>Max. quantity is 1,000,000</>";      
		      document.getElementById('quantity').value = "1000000";
		      quantity = 1000000;
		   } 
		   
		   //clear warning if it is normal
		   else {
		   		document.getElementById('quantity_alert').innerHTML = "";
		   }
	 }
	 else {
	 		 document.getElementById('quantity_alert').innerHTML = "<font size=1 color=red>Number Only</>";  
		   document.getElementById('quantity').value = "5";  
		   quantity = 5; 
	 }
  
   var subtotal = quantity * 268;
   calShipping();
   var shipping = document.getElementById('shipping').value;
	 var total = parseInt(shipping) + parseInt(subtotal);
   document.getElementById('subtotal').value = subtotal;
	 document.getElementById('total').value = total;
}

function calShipping() {
   var shipping = 0;
   var zone = document.getElementById('country').value;
   zone = zone.substr(0,2);
   var quantity = document.getElementById('quantity').value;
   var subtotal = document.getElementById('subtotal').value;
   switch (zone) {
      case 'A0':
      shipping = 14 + ((quantity-1) * 3);
      break;
      case '10':
      shipping = 27 + ((quantity-1) * 5);
      break;
      case '20':
      shipping = 27 + ((quantity-1) * 5);
      break;
      case 'B0':
      shipping = 18 + ((quantity-1) * 5);
      break;           
      case 'C0':
      shipping = 21 + ((quantity-1) * 5);
      break;      
      case 'D0':
      shipping = 24 + ((quantity-1) * 5);
      break;      
      case 'E1':
      shipping = 43 + ((quantity-1) * 6);
      break;
      case 'E0':
      shipping = 37 + ((quantity-1) * 5);
      break;            
      case 'F1':
      shipping = 53 + ((quantity-1) * 9);
      break;       
      case 'H1':
      shipping = 74 + ((quantity-1) * 17);
      break;     
      case 'G1':
      shipping = 74 + ((quantity-1) * 14);
      break;     
      case 'F0':
      shipping = 44 + ((quantity-1) * 8);
      break; 
      case 'G0':
      shipping = 61 + ((quantity-1) * 12);
      break;  
      case 'HK':
      shipping = 25 + Math.round((quantity-1) * (25/8));
      break;   
      default:
      shipping = 0;
                   
   }
   var total = shipping + parseInt(subtotal);
   document.getElementById('shipping').value = shipping;
   document.getElementById('total').value = total;
}

function checkempty(fieldname, inputtext){
	 if ( document.getElementById(fieldname).value == "" ) {
	  	document.getElementById(fieldname+'_e').innerHTML='Please fill in the '+ inputtext;
	} else {
		document.getElementById(fieldname+'_e').innerHTML='';
	};
}

function checknumber(fieldname, defaultValue, inputlength, alertbox, alertmessage){
	 var inputvalue = document.getElementById(fieldname).value;
	 var numpatt = /\D/g;
	 var message = "";
	 if((inputvalue.search(numpatt) != -1) || (inputvalue == "")) {
	 	document.getElementById(fieldname).value = defaultValue;
	 	message = alertmessage;
	}
	 else {
	 	if(inputvalue.length != inputlength) {
	 		document.getElementById(fieldname).value = defaultValue;
	 		message = "Please input " + inputlength + " digits";
	 	}
	 	else {
	 		message = "";
	 	}
	}
	 if(alertbox) {
	 	document.getElementById(alertbox).innerHTML = message;
	}
}

function showdetails(fieldname) {
	if(document.getElementById(fieldname).innerHTML.length > 20) {
		document.getElementById(fieldname).innerHTML = "Altai C1 Super WiFi CPE/AP";
	}
	else {
		document.getElementById(fieldname).innerHTML = "Altai C1 Super WiFi CPE/AP with<br />- 1 x DC injector<br />- 1 x AC power adaptor (UK)<br />- 1 x table stand<br />- 1 x quick setup guide";
		window.open('images/products/c1_accessories.jpg', 'blank', 'toolbar=no, width=350, height=450, resizable=no');
	}
}

function checkphone(sample){
var patt1 = /[a-zA-Z_]+/g;
var result = document.getElementById(sample).value.match(patt1);
if ( result ) {
	document.getElementById(sample+'_e').innerHTML='Your ' + sample.replace(/_/g, " ") + ' is invalid';
	document.getElementById(sample).value = "";
}

}

function checkemail(email){
var patt1 = /^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$/g;  
var result = document.getElementById(email).value.match(patt1);
if ( !(result) && document.getElementById(email).value!='') {
	document.getElementById(email+'_e').innerHTML='Your ' + email.replace(/_/g, " ") + ' is invalid';
	document.getElementById(email).value = "";
}
}

function checkcardexpiry(yearinput, monthinput) {
var d = new Date();
var patty = /\d{2}/;
var pattm = /\d{2}/;
var yearvalue = document.getElementById(yearinput).value;
var monthvalue = document.getElementById(monthinput).value;
var result1 = yearvalue.match(patty);
var result2 = monthvalue.match(pattm);
var currentyear = 1970 + Math.floor(d.getTime() / (1000 * 60 * 60 * 24 * 365));
var month = Math.abs(Math.round(monthvalue));

var message = "";

if (result1) {
	if ((2000 + yearvalue) < currentyear) {
		result1 = 0;
	}
}

if (result2) {
	if ((month < 1) || (month > 12)) {
		result2 = 0;
	}
}

if (!result1) {
	if (!result2) {
		document.getElementById('card_expiry_e').innerHTML='Invalid Card Expiry: Year, Month';
		document.getElementById(yearinput).value = "";
		document.getElementById(monthinput).value = "";
	}
	else {
		document.getElementById('card_expiry_e').innerHTML='Invalid Card Expiry: Year';
		document.getElementById(yearinput).value = "";
	}
}
else {
	if (!result2) {
		document.getElementById('card_expiry_e').innerHTML='Invalid Card Expiry: Month';
		document.getElementById(monthinput).value = "";
	}
	else {
		document.getElementById('card_expiry_e').innerHTML='';
	}
}

}


function setStyle(x)
{
document.getElementById(x).style.background="#cccccc";
}