function chk_data() {
         if ( add_form.Name.value == "" ) {
              alert("Please insert your name");
              add_form.Name.focus();}
         else if ( add_form.Telephone.value == "" ) {
                alert("Please insert your contact number");
                add_form.Telephone.focus();}
	else if ( add_form.Mobile.value == "" ) {
                alert("Please insert your mobile number");
                add_form.Mobile.focus();}

	else if ( add_form.Email.value == "" ||  add_form.Email.value.indexOf == -1 ){
                   alert("Please insert your email address");
                   add_form.Email.focus();}
         else if ( add_form.Email.value == "" || ( add_form.Email.value.indexOf('@',0) == -1 ||
                   add_form.Email.value.indexOf('.',0) == -1 )) {
                   alert("Plese insert a right email address");
                   add_form.Email.focus();}
         else { return true; }
         return false;
}