function validate(){


 if(document.newletter.firstname.value==""){
  alert("Please Enter Your First Name!");
  document.newletter.firstname.focus();
  return false;
 }
 if(document.newletter.lastname.value==""){
  alert("Please Enter Your Last Name!");
  document.newletter.lastname.focus();
  return false;
 }

 if(document.newletter.email.value==""){
  alert("Please Enter Your E-mail ID!");
  document.newletter.email.focus();
  return false;
 }
 
 var str=document.newletter.email.value
 var filter=/^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i
 if (filter.test(str)){ 
 }else{
 alert("Please input a valid email address!");
 document.newletter.email.focus();
 return false;
 }
}