const min = $("#min_rel"); const max = $("#max_rel"); const none = $("#min_rel option:first-child").attr("value"); const warning = $("#minmax_warning"); function ver_check() { const minv = min.val(); const maxv = max.val(); if (minv != none && maxv != none && minv > maxv) { warning.show(); } else { warning.hide(); } } min.change(ver_check); max.change(ver_check);