이메일 자바스크립트

function Sel_Email()
{
 f = document.form1;
 s_email = f.email_kind[f.email_kind.selectedIndex].value;

 switch(s_email)
 {
  case "" :
  f.email2.value="";
  f.email2.readOnly = true;
  f.email2.style.backgroundColor = "#efefef";
  break;
  case "etc" :
  f.email2.value="";
  f.email2.readOnly = false;
  f.email2.style.backgroundColor = "#ffffff";
  break;
  default :
  f.email2.value=s_email;
  f.email2.readOnly = true;
  f.email2.style.backgroundColor = "#efefef";
  break;
 }
}