Adding "Must Agree To Terms" to Register Form

HTML & CSS
1

How can I add a “Must Agree To Terms” to this Register Form so, that they must check that they read the Terms (from a linked page) in order to Submit?

Here is the basic Registration Form code:

<form action='form_handle.php' method='post'>
<table border='0' padding='0' spacing='0' >
<tr>
<td>Company Name:</td>
<td><input type='text' size='35' name='company_name'></td>
</tr>

<tr>
<td>Address:</td>
<td><input type='text' size='20' name='address'></td>
</tr>

<tr>
<td>City:</td>
<td><input type='text' size='20' name='city'></td>
</tr>
<tr>
<td>State:</td>
<td><input type='text' size='4' name='ztate'></td>
</tr>

<tr>
<td>Zip:</td>
<td><input type='text' size='9' name='zip'></td>
</tr>

<tr>
<td>Contact Name:</td>
<td><input type='text' size='20' name='contact_name'></td>
</tr>

<tr>
<td>Phone Number:</td>
<td><input type='text' size='15' name='phone_number'></td>
</tr>
<tr>
<td>Email Address:</td>
<td><input type='text' size='15' name='email_address'></td>
</tr>

<tr>
<td>Description:</td>
<td><textarea name='Description' rows='10' cols='80'></textarea></td>
</tr>

<tr>
<td colspan='2' align='right'><input type='submit' value = 'Register'></td>
</tr>

</table>
</form>
2

XHTML code


<input type="checkbox" name="agree" id="agree" value="agree" /> <label for='agree'>Do you agree to the terms?</label>

Javascript validation:


function validate()
{
if(false == document.getElementById("agree").checked)
{
alert("If you agree with the terms, check the Agree check box");
}
}

Serverside (PHP):


if(empty($_POST['agree']) || $_POST['agree'] != 'agree')
{
echo "If you agree with the terms, check the Agree check box";
exit;
}