function valid_login()
{

var username = document.login.username.value
if(username==""){
	   	 alert("Please enter your username");
		 document.login.username.focus()
	     return false
	}
var password = document.login.password.value
if(password==""){
	   	 alert("Please enter your password");
		 document.login.password.focus()
	     return false
	}
}