function phpbb_switch_tz_date(keep_selection) { var timezone_groups = document.getElementById("timezone"); for (var i = 0; i < timezone_groups.childElementCount; i++) { if (timezone_groups.children[i].tagName == "OPTGROUP" && timezone_groups.children[i].label != document.getElementById("tz_date").value) { timezone_groups.children[i].style.display = "none"; } else if (timezone_groups.children[i].tagName == "OPTGROUP") { // Display other options timezone_groups.children[i].style.display = "block"; } } if (typeof keep_selection !== 'undefined') { if (!keep_selection) { timezone_groups.children[0].selected = true; } } } function phpbb_enable_tz_dates() { var tz_select_date = document.getElementById("tz_select_date"); tz_select_date.style.display = "block"; }