Validate date/time input

// Validates date/time value (mm/dd/yyyy hh:mm:ss AM|PM)
function validateDateTime(value, errorOnEmpty) {
    // capture all the parts (mm/dd/yyyy hh:mm:ss AM|PM)
    var matches = value.match(/^(\d{1,2})\/(\d{1,2})\/(\d{4}) (\d{1,2}):(\d{2}):(\d{2})\s*(AM|PM)$/i);

    var isValid = true;

    if (errorOnEmpty == true && (value == '' || value == null)) {
        // invalid
        isValid = false;
    } else if (value != '' && value != null) {
        //alt:
        // value.match(/^(\d{2}).(\d{2}).(\d{4}).(\d{2}).(\d{2}).(\d{2})$/);
        // also matches 22/05/2013 11:23:22 and 22a0592013,11@23a22
        if (matches === null) {
            // invalid
            isValid = false;
        } else {
            // now lets check the date sanity
            var year = parseInt(matches[3], 10);
            var month = parseInt(matches[2], 10) - 1; // months are 0-11
            var day = parseInt(matches[1], 10);
            var hour = parseInt(matches[4], 10);
            var minute = parseInt(matches[5], 10);
            var second = parseInt(matches[6], 10);
            // Convert AM/PM values to 24 hour time
            if (matches[7].toUpperCase() == 'PM') {
                if (hour < 12) {
                    hour = hour + 12;
                } else if (hour > 12) {
                    // invalid
                    isValid = false;
                }
            } else if (matches[7].toUpperCase() == 'AM') {
                if (hour > 12) {
                    // invalid
                    isValid = false;
                } else if (hour == 12) {
                    hour = 0;
                }
            }
            if (isValid == true) {
                var date = new Date(year, month, day, hour, minute, second);
                if (date.getFullYear() !== year
                    || date.getMonth() != month
                    || date.getDate() !== day
                    || date.getHours() !== hour
                    || date.getMinutes() !== minute
                    || date.getSeconds() !== second
                ) {
                    // invalid
                    isValid = false;
                } else {
                    // valid
                    isValid = true;
                }
            }
        }
    } else {
        // valid
        isValid = true;
    }

    return isValid;
}