function open_printrates() 
	{
		window.open('printrates.php','tarife','scrollbars=yes, status=yes, menubar=yes, toolbar=yes, location=no, resizable=yes, width=700,height=450');
		return false;
	}
	
	function isEmail(address) {
		var isValid = false;
		// basic checks (relying on lazy evaluation for correct behaviour!)
		// not empty
		// at least 7 characters (x@yy.zz)
		// has @
		// has only 1 @
		// has at least one . (domain.ext)
		isValid = (address!=null) 
		       && (address.length >= 7) 
		       && (address.indexOf('@')!=-1) 
		       && (address.indexOf('@') == address.lastIndexOf('@'))
		       && (address.indexOf('.')!=-1)
		;
		
		if (isValid) {
			var parts = address.split('@');
			var name  = parts[0].split('.');
			var host  = parts[1].split('.');
			var regName  = new RegExp("^([!#$%&'*+-/0-9=?A-Z^_a-z{}~]+)$"); // at least length 1
			var regLabel = new RegExp("^(^[-0-9A-Za-z][-0-9A-Za-z]+)$"); // at least length 2
			var regExt   = new RegExp("^([A-Za-z]{2,63})$"); // at least length 2
			var i;
			for (i=0; i < name.length; i++) {
				isValid = isValid && (name[i].search(regName) != -1);
			}
			for (i=0; i < host.length-1; i++) {
				isValid = isValid && (host[i].search(regLabel) != -1) && (host[i].length <= 63);
			}
			isValid = isValid && (host[host.length-1].search(regExt) != -1);
		}
		return isValid;
	}


	function noenter() {
		return !(window.event && window.event.keyCode == 13); 
	}

	function checkEmail(thisform)
	{
		var emailaddress = thisform.email.value;
		if (isEmail(emailaddress)) return true;
		else
		{
			alert('Your email address is incorrect.');
			return false;
		}
	}