"americandate": {                                     //  Check if date is valid by leap year                 "func": function (field) {                         var pattern = new RegExp(/^(0?[1-9]|1[012])[\/\-](0?[1-9]|[12][0-9]|3[01])[\/\-](\d{4})$/);                         var match = pattern.exec(field.val());                          if (match == null)                            return false;                          var year = match[3];                         var month = match[1]*1;                         var day = match[2]*1;                                            var date = new Date(year, month - 1, day); // because months starts from 0.                         return (date.getFullYear() == year && date.getMonth() == (month - 1) && date.getDate() == day);                     },                                       "alertText": "* Invalid date, must be in MM/DD/YYYY format"             }, where to call the function americandate?