function popupWindow(url) { 
	popup_window = window.open(url,'popupWindow','toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=no,copyhistory=no,width=442,height=630,screenX=0,screenY=0,top=0,left=0')
	popup_window.focus(); 
	if (!popup_window.opener) popup_window.opener=self;
}

function checkContact(){
	$form = document.forms['contact'];
	
	if(document.contact.yourname.value==""){
		alert('Ban Can Phai Nhap Ho Ten');
		return false;
	}
	if(document.contact.youremail.value==""){
		alert('Ban Can Phai Nhap 1 Dia Chi Email');
		return false;
	}
	if(document.contact.subject.value==""){
		alert('Ban Can Phai Nhap Noi Dung');
		return false;
	}
	
//Check Dia Chi Email
 var testresults
 var str= document.contact.youremail.value
 var filter=/^.+@.+\..{2,3}$/

 	if (filter.test(str))
    	testresults=true
	 else {
	    alert("Dia chi Email cua ban ko hop le !")
	    document.contact.youremail.focus();
    	return false;
	}
	return true;	
}