function check()
{
  var form=document.forms["register"];
  if (form.email.value.length != 0)
  {
    if (form.email.value.charAt(0) == "." || form.email.value.charAt(0) == "@" || form.email.value.indexOf('@', 0) ==  - 1 || form.email.value.indexOf('.', 0) ==  - 1 || form.email.value.lastIndexOf("@") == form.email.value.length - 1 || form.email.value.lastIndexOf(".") == form.email.value.length - 1)
    {
      alert("Email address format is not correct! ");
      form.email.focus();
      return false;
    }
  }
  else
  {
    alert("Email not empty! ");
    form.email.focus();
    return false;
  }
  if (IsNull(form.Firest_Name.value))
  {
    alert("Your Firest_Name Not is null, please input!");
    form.Firest_Name.focus();
    return false;
  }
  if (IsNull(form.Last_Name.value))
  {
    alert("Your last Name Not is null, please input!");
    form.Last_Name.focus();
    return false;
  }
  if (IsNull(form.password.value) || form.password.value.length < 6)
  {
    alert("Password Length must >6,please input!");
    form.password.focus();
    return false;
  }
  if (form.password.value != form.re_pass.value)
  {
    form.password.value = '';
    form.re_pass.value = '';
    alert("Two different input password, please re-entry. ");
    form.password.focus();
    return false;
  }
}