function Validate() {

    var invalid = " ";	

    if(document.forms[0].myname.value=="")
        {alert("Please input your name");
		 document.forms[0].myname.focus();
		 return;	
		}	
    if(document.forms[0].myemail.value=="")
        {alert("Please input your e-mail");
		 document.forms[0].myemail.focus();
		 return;	
		}	
    if(document.forms[0].namea.value=="")
        {alert("Please input your friend's name");
		 document.forms[0].namea.focus();
		 return;	
		}	
    if(document.forms[0].emaila.value=="")
        {alert("Please input your friend's email");
		 document.forms[0].emaila.focus();
		 return;	
		}	
	else 
	{
	document.forms[0].submit();
	}
	
}