仅当指定的样式存在时，用JavaScript验证字段-不使用jQuery验证

我有一个表单，只有在选中相应的单选按钮时才需要字段。我把这个网站插入有太多的问题与jQuery，所以我希望做的验证只有JavaScript -我不能得到jQuery验证插件正确工作。我是JavaScript和jQuery的初学者。

列表元素中包含的字段根据单选按钮使用jQuery显示/隐藏。列表元素以内联的"display: none;"开始。是否有一种方法与JavaScript，我可以运行验证，只有当列表项的内联样式与id是"显示:块"?

我在这上面花了太长时间，快疯了。

        <form name="pancettaForm" method="post" action="http://lizlantz.com/lcform.php" id="pancettaForm" onsubmit="return validateForm()">
                <input type="hidden" value="Pancetta Order Update" name="subject"> 
                <input type="hidden" value="cookware/partners_10151_-1_20002" name="redirect">
                <ul>
                    <li>
                    <label for="updateShip">I'd like to:</label> 
                        <input id="ship-address" name="updateShip" type="radio" value="update-ship-address" class="required"/> Have pancetta shipped to a different address than my skillet<br />
                        <input id="ship-date" name="updateShip" type="radio" value="update-ship-date" class="required" /> Have pancetta shipped sooner than June 14, 2013 <br />
                        <input id="ship-both" name="updateShip" type="radio" value="update-both"  class="required"/> Make changes to both the shipping address and shipping date
                    </li>
                    <li>                
                    <label for="order-number"><em>*</em>Order Number (available in order confirmation email):</label> 
                        <input type="text" name="order-number" class="required">
                    </li>             
                    <li>                
                    <label for="full-name"><em>*</em>Recipient Full Name:</label> 
                        <input type="text" name="full-name" class="required">
                    </li>   
                    <li id="address" style="display: none;">
                        <label for="address">
                            <em>*</em>Address
                        </label> 
                        <input type="text" name="address">
                        <label for="address2">
                            Address Line 2
                        </label> 
                        <input type="text" name="address2">
                    </li>
                    <li id="address2" style="display: none;">
                        <label for="city">
                            <em>*</em>City
                        </label> 
                        <input type="text" name="city">
                        <label for="state">
                            <em>*</em>State
                        </label> 
                        <select name="state">
                            <option>- Select State -</option>                            
                            <option value="AL">Alabama</option>
                            <option value="AK">Alaska</option>
                        </select>
                        <label for="zip">
                            <em>*</em>Zip Code
                        </label> 
                        <input type="text" name="zip">
                    </li>
                    <li id="new-ship-date" style="display: none;">
                        <label for="New Ship Date"><em>*</em>New Ship Date (Saturday-Tuesday delivery not available):</label>                 
                        <select name="newShip" id="newShip">
                            <option>- Select -</option>
                            <option value="Wednesday, May 22">Wednesday, May 22</option>
                            <option value="Thursday, May 23">Thursday, May 23</option>
                        </select>                            
                    </li>                       
                    <li>
                        <label for="phone">
                            <em>*</em>Phone (for delivery questions)
                        </label> 
                        <input type="text" name="phone" class="required">
                    </li>               
                </ul>
                       <input type="submit" id="button" name="submit"  value="Update Pancetta">
              </form>

这是我使用的jQuery:

            $j(document).ready(function() {
                $j('#pancettaForm').change(function () {
                           $j('#address,#address2,#new-ship-date').hide();
                           if ($j('#ship-address').prop('checked')) {
                              $j('#address, #address2').show();
                           }
                           else if ($j('#ship-date').prop('checked')) {
                              $j('#new-ship-date').show();
                           }
                           else if ($j('#ship-both').prop('checked')) {
                              $j('#address, #address2, #new-ship-date').show();
                           }
                        });
            });

，这是目前为止我的验证脚本的一般结构:

            function validateForm()
            {
                var x=document.forms["pancettaForm"]["order-number"].value;
                if (x==null || x=="")
                  {
                  alert("Please provide your order number.");
                  return false;
                  }
                var x=document.forms["pancettaForm"]["full-name"].value;
                if (x==null || x=="")
                  {
                  alert("Please provide your full name.");
                  return false;
                  }
                var x=document.forms["pancettaForm"]["Address1"].value;
                if (x==null || x=="")
                  {
                  alert("Please provide your address.");
                  return false;
                  }
                var x=document.forms["pancettaForm"]["city"].value;
                if (x==null || x=="")
                  {
                  alert("Please provide your city.");
                  return false;
                  }
               if( document.pancettaForm.state.value == "- Select State -" )
               {
                 alert( "Please provide your state." );
                 return false;
               }
                var x=document.forms["pancettaForm"]["zip"].value;
                if (x==null || x=="")
                  {
                  alert("Please provide your zip code.");
                  return false;
                  }  

                var x=document.forms["pancettaForm"]["Zip_Code"].value;
                if (x==null || x=="")
                  {
                  alert("Please provide your zip code.");
                  return false;
                  } 
                  if( document.pancettaForm.newShip.value == "- Select Date -" )
               {
                 alert( "Please select the size of the product you would like to register.  " );
                 return false;
               }

            }