How can I validate this as one hidden field. I have 3 dropbdown list month, day, year and I do not want to validate each separate on so I would like to combine the strings together and validate the hidden field. Pleas and thank you for your help.
<!-- DOB --> <fieldset id="section-dob" class="group"> <legend><span>Birth date</span></legend> <!-- Month --> <div> <label for="dob_month">Month</label> <select name="month" value="" id="month" onchange="document.getElementById('birthdate').value = document.getElementById('month').value + '/' + document.getElementById('day').value + '/' + document.getElementById('year').value; "> <option selected="selected" value="" >Month</option> <?php for($i=1;$i<=12;$i++) { echo "<option>" . $i . "</option>"; } ?> </select> </div> <!-- Day --> <div> <label for="dob_day">Day</label> <select name="day" value="" id="day" onchange=" document.getElementById('birthdate').value = document.getElementById('month').value + '/' + document.getElementById('day').value + '/' + document.getElementById('year').value; "> <option selected="selected" value="">Day</option> <?php for($i=1;$i<=31;$i++) { echo "<option>" . $i . "</option>"; } ?> </select> </div> <!-- Year --> <div> <label for="dob_year">Year</label> <select name="year" value="" id="year" onchange=" document.getElementById('birthdate').value = document.getElementById('month').value + '/' + document.getElementById('day').value + '/' + document.getElementById('year').value; "> <option selected="selected" value="">Year</option> <?php for($i=2005;$i<=2008;$i++) { echo "<option>" . $i . "</option>"; } ?> </select>