Form Validation not working with tel, email and select - html

Question

I use Dreamweaver to write my html code, but now have run into a problem.
I have created an enquiry form which contains several different fields, but when I try to validate the form using Window | Behavior | Validate Form, it only shows my "firstname", "lastname", "Datepicker1", "Datepicker2" as well as the "Comments" field.
I want to make sure that the telephone, email and select fields are required and will be filled by a number and an email address. It worked fine when I made the contact form, but for some reason it does not in the enquiry.
My code is as follows:
<form action="../../enquiryform.php" method="post" id="enquiry">
<h1>ENQUIRE ABOUT<br><span style="color:#816122">VILLA 2610</span></h1>
<input type="hidden" name="villaid" id="villaid" value="2610">
<br>
Arrival Date<br>
<input type="text" name="arrivaldate" id="Datepicker1">
<br>Departure Date<br>
<input type="text" name="departuredate" id="Datepicker2"><br>
First Name
<input type="text" name="firstname" id="firstname"><br>
Last Name
<input type="text" name="lastname" id="lastname"><br>
Telephone
<input type="tel" name="tel" id="tel"><br>
Email
<input type="email" name="email" id="email"><br>
<div class="leftcolumn">Adults<br>
<select name="adults" id="adults">
<option value=""> </option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6">6</option>
<option value="7">7</option>
<option value="8">8</option>
<option value="9">9</option>
<option value="10+">10+</option>
</select>
</div>
<div class="rightcolumn">Children<br>
<select name="children" id="children">
<option value=""> </option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6">6</option>
<option value="7">7</option>
<option value="8">8</option>
<option value="9">9</option>
<option value="10+">10+</option>
</select>
</div>
Comments (optional)<br>
<textarea name="comments" id="comments" wrap="soft" style="width:150px; height:100px;"></textarea><br>
<p class="antispam">Leave this empty: <input name="url" type="text" id="url" /></p>
<input type="submit" value="Send" style="background-color:#aa802c; color:#FFFFFF; border-radius:5px; text-align:center; cursor:pointer;"><br><br>
I have added the following inside the starting form bracket:
onSubmit="MM_validateForm('firstname','','R','lastname','','R');return document.MM_returnValue"
But what should I use for a telephone number, email address as well as the 2 select options that I have?
My suggestion is
onSubmit="MM_validateForm('firstname','','R','lastname','','R','tel','','RisNum','email','','RisEmail',);return document.MM_returnValue"
But how do I add that I require for my viewers to select children and adults options?
And are my thoughts above correct?

Answer 1

Why don't you use the require attribute on input tag like this
Telephone
<input type="tel" name="tel" id="tel" required>