https://fn2.uni-regensburg.de/FN2HtmlLib/js/jquery.date_input.de_DE.js?v=26940a229152acda5c0942f9655a9c83

1const CUSTOM_DATE_INPUT_SETTINGS = {
2  month_names: ["Januar", "Februar", "März", "April", "Mai", "Juni", "Juli", "August", "September", "Oktober", "November", "Dezember"],
3  short_month_names: ["Jan", "Feb", "Mär", "Apr", "Mai", "Jun", "Jul", "Aug", "Sep", "Okt", "Nov", "Dez"],
4  short_day_names: ["So", "Mo", "Di", "Mi", "Do", "Fr", "Sa"],
5  stringToDate: function(string) {
6    let matches;
7    if (matches = string.match(/^(\d{1,2})\.(\d{1,2})\.(\d{4})$/)) {
8      return new Date(Number(matches[3]), Number(matches[2]) - 1, Number(matches[1]));
9    } else {
10      return null;
11    };
12  },
13  dateToString: function(date) {
14    let month = (date.getMonth() + 1).toString();
15    let dom = date.getDate().toString();
16    return  String(dom).padStart(2, "0") + "." + String(month).padStart(2, "0") + "." + date.getFullYear();
17  },
18  show: function () {
19    this.rootLayers.css("display", "block");
20    this.setPosition();
21    this.input.off("focus");
22    this.input.on("keydown", this.hide);
23    $([window, document.body]).on("click",this.hideIfClickOutside);
24  },
25  hide: function (e) {
26    // Falls das event keydown war und nicht TAB wird hide Funktion abgebrochen.
27    if(e && e.type === 'keydown' && e.keyCode !== 9) return;
28    this.rootLayers.css("display", "none");
29    $([window, document.body]).off("click", this.hideIfClickOutside);
30    this.input.on("focus",this.show);
31    this.input.off("keydown");
32  },
33};
34
35/**
36 * Initialisiert das date_input-Plugin mit CUSTOM Settings, sodass es mit dem FN2-Datums-Format kompatibel ist
37 * @param target  Input-Feld, dem der Date-Picker zugewiesen werden soll.
38 */
39function initDateInput(target) {
40  target.date_input(CUSTOM_DATE_INPUT_SETTINGS);
41}