function ValidateForm(f){

  with(f){
    if (isEmpty(_1_Name.value)) {
      alert("Please enter your Name");
      _1_Name.focus();
      return false;
    }

    if ( !isEmail(_2_Email_From.value) ) {
      alert("Please enter a valid Email Address.");
      _2_Email_From.focus();
      return false;
    }

    if (isEmpty(_3_Phone.value)) {
      alert("Please enter your Phone number");
      _3_Phone.focus();
      return false;
    }

    if (isEmpty(_4_Enquiry.value)) {
      alert("Please enter your query in the comments field");
      _4_Enquiry.focus();
      return false;
    }

  }
  return true;
}