validering af dato og text-input

Følgende script validerer på dato for gyldighed, hvilket fungere perfekt:

<SCRIPT LANGUAGE="JavaScript">

<!-- Begin

function isValidDate(dateStr) {
    // Checks for the following valid date formats:
    // dd-mm-yyyy  dd.mm.yyyy
    // Also separates date into day, month, and year variables

    var datePat = /^(\d{1,2})(\.|-)(\d{1,2})\2(\d{4})$/;

    var matchArray = dateStr.match(datePat); // is the format ok?
    if (matchArray == null) {
        alert("Date is not in a valid format.")
        return false;
    }
    // parse date into variables
    day = matchArray[1];
    month = matchArray[3];
    year = matchArray[4];
    if (month < 1 || month > 12) { // check month range
        alert("Month must be between 1 and 12.");
        return false;
    }
    if (day < 1 || day > 31) {
        alert("Day must be between 1 and 31.");
        return false;
    }
    if ((month==4 || month==6 || month==9 || month==11) && day==31) {
        alert("Month "+month+" doesn't have 31 days.")
        return false
    }
    if (month == 2) { // check for february 29th
        var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
        if (day>29 || (day==29 && !isleap)) {
            alert("February " + year + " doesn't have " + day + " days.");
            return false;
        }
    }
    var toDay = new Date()//sets today date
    var newDate = new Date(year,month-1,day)//sets the new input date
    var dif = newDate-toDay;//difference in miliseconds
    dif = Math.ceil(dif/1000/60/60/24);//difference in days
    if(dif<0){//if the date is in the past
        alert('The date is in the past. Please input a valid date!');
        //document.forms[0].elements['date'].value='';
        return false;
    }
   
    return true;  // date is valid
}
//  End -->
</SCRIPT>

<FORM ACTION="" METHOD="post" onSubmit="return isValidDate(this.date.value);">
Skriv dato:  <INPUT TYPE="text" NAME="date" SIZE="10" MAXLENGTH="10"> (dd.mm.åååå) 
<INPUT TYPE="submit" VALUE="Dato"><BR>


Problemet er, at jeg forsøgt på at tilføje et obligatorisk text-felt (headline). Et eller andet går galt, for der sker intet, dvs. ej heller dato-valideringen virker længere. Dette script virker altså ikke:

<SCRIPT LANGUAGE="JavaScript">
<!-- Begin

function isValidDate() {
    if (myForm.headline.match.value == null){
        alert("Headline is missing.");
        return false;
    }
    // Checks for the following valid date formats:
    // dd-mm-yyyy  dd.mm.yyyy
    // Also separates date into day, month, and year variables

    var datePat = /^(\d{1,2})(\.|-)(\d{1,2})\2(\d{4})$/;

    var matchArray = myForm.date.match.value(datePat); // is the format ok?
    if (matchArray == null) {
        alert("Date is not in a valid format.")
        return false;
    }
    // parse date into variables
    day = matchArray[1];
    month = matchArray[3];
    year = matchArray[4];
    if (month < 1 || month > 12) { // check month range
        alert("Month must be between 1 and 12.");
        return false;
    }
    if (day < 1 || day > 31) {
        alert("Day must be between 1 and 31.");
        return false;
    }
    if ((month==4 || month==6 || month==9 || month==11) && day==31) {
        alert("Month "+month+" doesn't have 31 days.")
        return false
    }
    if (month == 2) { // check for february 29th
        var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
        if (day>29 || (day==29 && !isleap)) {
            alert("February " + year + " doesn't have " + day + " days.");
            return false;
        }
    }
    var toDay = new Date()//sets today date
    var newDate = new Date(year,month-1,day)//sets the new input date
    var dif = newDate-toDay;//difference in miliseconds
    dif = Math.ceil(dif/1000/60/60/24);//difference in days
    if(dif<0){//if the date is in the past
        alert('The date is in the past. Please input a valid date!');
        //document.forms[0].elements['date'].value='';
        return false;
    }
    return true;  // date is valid
}
//  End -->
</SCRIPT>

<FORM ACTION="" METHOD="post" onSubmit="return isValidDate();">
Skriv dato:  <INPUT TYPE="text" NAME="date" SIZE="10" MAXLENGTH="10"> (dd.mm.åååå)<BR>
Tekst: <TEXTAREA COLS="70" ROWS="2" NAME="headline" WRAP=virtual></TEXTAREA><BR>
<INPUT TYPE="submit" VALUE="Dato"><BR>
</FORM>