my @textfield_args = ( -name => 'name', ..., -maxlength => 120, );
if( $was_no_change ) {
  push @textfield_args, -onfocus => 'this.value = ''";
  push @textfield_args, -onblur => 'this.value = 'def'";
  push @textfield_args, -onchange => 'delete onfocus, delete onblur";
}

$string .= $cgi->textfield( @textfield_args );