(see guidelines for overcoming access barriers)
Automatic form submissions and auto-jumps with drop down lists are not easily interpreted by adaptive technologies. Always include a button for the user to select when they are ready to continue.
<form name="month" id="month" action="#">
<p>Which month were you born in:
<select name="month" id="month" tabindex="1">
<option label="January" value="1">January</option>
<option label="February" value="2">February</option>
<option label="March" value="3">March</option>
<option label="April" value="4">April</option>
<option label="May" value="5">May</option>
<option label="June" value="6">June</option>
<option label="July" value="7">July</option>
<option label="August" value="8">August</option>
<option label="September" value="9">September</option>
<option label="October" value="10">October</option>
<option label="November" value="11">November</option>
<option label="December" value="12">December</option>
</select>
</p>
<p><input type="submit" name="Submit2" id="Submit2" value="Submit"></p>
</form>