需要下拉菜单

Question

我需要在注册页面时使我的下拉菜单成为必填字段。我对我的下拉菜单也做了同样的处理，我为文本框和复选框完成了所有工作，因此不能理解为什么下拉不是。这是我与其他人完成的整个形式。谢谢

<form action="Home.html" method="post" name="form1" onsubmit="Display()"> 
    <table bgcolor="white" width="700" border="0" align="center"> 
    <col width="200"> 
    <col width="200"> 


    <tr> 
    <th colspan = "2" align = "center" bgcolor="grey"> Fill the form to sign up. </th> 
    </tr> 
<tr> 
    <td>&nbsp;</td> 
    </tr> 


    <tr> 
    <td colspan="2" style="font-size:12px">Fields marked with * are mandatory</td> 
    </tr> 


    <tr> 
    <td>&nbsp;</td> 
    </tr> 


    <tr> 
     <td>Forename*</td> 
     <td>Surname*</td> 
    </tr> 


    <tr> 
     <td><label> 
     <input type="text" name="txtname" id="txtname" class="info" required> 
     <td><label> 
     <input type="text" name="txtsurname" id="txtsurname" class="info" required /> 
     </label></td> 
    </tr> 

    <tr> 
    <td> Create Username*</td> 
    <td> Birthday</td> 
    </tr> 

    <tr> 
    <td><label> 
    <input type="text" name="txtusername" id="txtusername" class="info" required/> 
    </label></td> 




    <td><select name="DOBMonth" required> 
    <option> Month </option> 
    <option value="January">January</option> 
    <option value="Febuary">Febuary</option> 
    <option value="March">March</option> 
    <option value="April">April</option> 
    <option value="May">May</option> 
    <option value="June">June</option> 
    <option value="July">July</option> 
    <option value="August">August</option> 
    <option value="September">September</option> 
    <option value="October">October</option> 
    <option value="November">November</option> 
    <option value="December">December</option> 
</select> 

<select name="DOBDay" required> 
    <option> Day </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> 
    <option value="11">11</option> 
    <option value="12">12</option> 
    <option value="13">13</option> 
    <option value="14">14</option> 
    <option value="15">15</option> 
    <option value="16">16</option> 
    <option value="17">17</option> 
    <option value="18">18</option> 
    <option value="19">19</option> 
    <option value="20">20</option> 
    <option value="21">21</option> 
    <option value="22">22</option> 
    <option value="23">23</option> 
    <option value="24">24</option> 
    <option value="25">25</option> 
    <option value="26">26</option> 
    <option value="27">27</option> 
    <option value="28">28</option> 
    <option value="29">29</option> 
    <option value="30">30</option> 
    <option value="31">31</option> 
</select> 

<select name="DOBYear" required> 
    <option> Year </option> 
    <option value="2016">2016</option> 
    <option value="2015">2015</option> 
    <option value="2014">2014</option> 
    <option value="2013">2013</option> 
    <option value="2012">2012</option> 
    <option value="2011">2011</option> 
    <option value="2010">2010</option> 
    <option value="2009">2009</option> 
    <option value="2008">2008</option> 
    <option value="2007">2007</option> 
    <option value="2006">2006</option> 
    <option value="2005">2005</option> 
    <option value="2004">2004</option> 
    <option value="2003">2003</option> 
    <option value="2002">2002</option> 
    <option value="2001">2001</option> 
    <option value="2000">2000</option> 
    <option value="1999">1998</option> 
    <option value="1998">1998</option> 
    <option value="1997">1997</option> 
    <option value="1996">1996</option> 
    <option value="1995">1995</option> 
    <option value="1994">1994</option> 
    <option value="1993">1993</option> 
    <option value="1992">1992</option> 
    <option value="1991">1991</option> 
    <option value="1990">1990</option> 
    <option value="1989">1989</option> 
    <option value="1988">1988</option> 
    <option value="1987">1987</option> 
    <option value="1986">1986</option> 
    <option value="1985">1985</option> 
    <option value="1984">1984</option> 
    <option value="1983">1983</option> 
    <option value="1982">1982</option> 
    <option value="1981">1981</option> 
    <option value="1980">1980</option> 
    <option value="1979">1979</option> 
    <option value="1978">1978</option> 
    <option value="1977">1977</option> 
    <option value="1976">1976</option> 
    <option value="1975">1975</option> 
    <option value="1974">1974</option> 
    <option value="1973">1973</option> 
    <option value="1972">1972</option> 
    <option value="1971">1971</option> 
    <option value="1970">1970</option> 
    <option value="1969">1969</option> 
    <option value="1968">1968</option> 
    <option value="1967">1967</option> 
    <option value="1966">1966</option> 
    <option value="1965">1965</option> 
    <option value="1964">1964</option> 
    <option value="1963">1963</option> 
    <option value="1962">1962</option> 
    <option value="1961">1961</option> 
    <option value="1960">1960</option> 
    <option value="1959">1959</option> 
    <option value="1958">1958</option> 
    <option value="1957">1957</option> 
    <option value="1956">1956</option> 
    <option value="1955">1955</option> 
    <option value="1954">1954</option> 
    <option value="1953">1953</option> 
    <option value="1952">1952</option> 
    <option value="1951">1951</option> 
    <option value="1950">1950</option> 
    <option value="1949">1949</option> 
    <option value="1948">1948</option> 
    <option value="1947">1947</option> 
</select> 




    <tr> 
     <td>Email*</td> 
     <td>Confirm Email*</td> 
    </tr> 


    <tr> 
     <td><label> 
     <input type="text" name="txtemail" id="txtemail" class="info" onchange="ValidateEmail(txtemail)" required /> 
     <td><label> 
     <input type="text" name="txtemail2" id="txtemail2" class="info" onchange="ValidateEmail2(txtemail2)" required/> 
     </label></td> 
    </tr> 


    <tr> 
     <td>Password*</td> 
     <td>Confirm Pasword*</td> 
    </tr> 


    <tr> 
     <td><label> 
     <input type="password" name="txtpassword" id="txtpassword" class="info" required/> 
     <td><label> 
     <input type="password" name="txtpassword2" id="txtpassword2" class="info" required/> 
     </label></td> 
    </tr> 


    <td colspan="2" style="font-size:12px">**Passwords must be at least 8 characters in lenght.</td> 
    </tr> 

    <tr> 
    <td>&nbsp;</td> 
    </tr> 


     <tr> 
     <td colspan="2"> 
     <label> 
      <input type="checkbox" name="terms" value="terms" id="terms" required/> 
      I agree to the Terms and Conditions</label> 
     </td></tr> 
     <br><br><br> 
     <tr> 
     <td colspan="2"><label> 
      <input type="checkbox" name="notify" value="notify" id="notify" /> 
      I want to receive notifications by text/email about new products in stock.</label> 
      </td> 
    </tr> 


    <tr> 
    <td>&nbsp;</td> 
    </tr> 

    <tr> 
    <td><label> 
     <input type="submit" name="Login" id="Login" value="Login" onclick="checkdetails() " /> 
    </label></td> 
    <td><label> 
     <input type="reset" name="Reset" id="Reset" value="Reset" /> 
    </label></td> 
    </tr> 

    <tr> 
    <td>&nbsp;</td> 
    </tr> 
    </table> 
</form> 

Answer 1

看来您需要将value=""添加到您的默认答案。例如，这应该为你的“DOBMonth”下拉菜单做的伎俩：

<select name="DOBMonth" required> 
<option value=""> Month </option> 
<option value="January">January</option> 
<option value="Febuary">Febuary</option> 
<option value="March">March</option> 
<option value="April">April</option> 
<option value="May">May</option> 
<option value="June">June</option> 
<option value="July">July</option> 
<option value="August">August</option> 
<option value="September">September</option> 
<option value="October">October</option> 
<option value="November">November</option> 
<option value="December">December</option> 
</select>