Javascript檢查多個下拉列表，條件返回false不工作

Question

我創建了多個下拉列表，並且檢查是否選擇了任何類下拉列表。然後，它應該警報，並且它正在這樣做，但問題是if條件中的其他函數也會觸發，儘管存在返回假條件

if條件只應在所有類下拉列表被選中時觸發

JS Fiddle demo

function addcourse() { 
 

 
    // The .each() method is unnecessary here: 
 
    $(".DD_Sub").each(function() { 
 

 
    if ($("option:selected", this).val() == " Select Subject "); { 
 

 
     alert(""); 
 
     return false; 
 
    } 
 
    
 
    }); 
 

 
    if ($("#BodyHolder_DDClass option:selected").text() == " Select Class ") { 
 

 
    alert("Select class"); 
 

 
    } 
 
    
 
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 
 
<select name="ctl00$BodyHolder$DD_Sub1" class="DD_Sub" style="height:27px;width:150px;"> 
 
    <option value="Select Subject">Select Subject</option> 
 
    <option value="Holiday">Holiday</option> 
 
    <option value="Lunch">Lunch</option> 
 
    <option value="ECO-20">ECO-20</option> 
 
    <option value="ECO-21">ECO-21</option> 
 
    <option value="ECO-22">ECO-22</option> 
 
    <option value="ENG-20">ENG-20</option> 
 

 
</select> 
 
<select name="ctl00$BodyHolder$DD_Sub1" class="DD_Sub" style="height:27px;width:150px;"> 
 
    <option value="Select Subject">Select Subject</option> 
 
    <option value="Holiday">Holiday</option> 
 
    <option value="Lunch">Lunch</option> 
 
    <option value="ECO-20">ECO-20</option> 
 
    <option value="ECO-21">ECO-21</option> 
 
    <option value="ECO-22">ECO-22</option> 
 
    <option value="ENG-20">ENG-20</option> 
 
</select> 
 
<select name="ctl00$BodyHolder$DD_Sub1" class="DD_Sub" style="height:27px;width:150px;"> 
 
    <option value="Select Subject">Select Subject</option> 
 
    <option value="Holiday">Holiday</option> 
 
    <option value="Lunch">Lunch</option> 
 
    <option value="ECO-20">ECO-20</option> 
 
    <option value="ECO-21">ECO-21</option> 
 
    <option value="ECO-22">ECO-22</option> 
 
    <option value="ENG-20">ENG-20</option> 
 
</select> 
 
<select name="ctl00$BodyHolder$DD_Sub1" class="DD_Sub" style="height:27px;width:150px;"> 
 
    <option value="Select Subject">Select Subject</option> 
 
    <option value="Holiday">Holiday</option> 
 
    <option value="Lunch">Lunch</option> 
 
    <option value="ECO-20">ECO-20</option> 
 
</select> 
 

 
<select name="ctl00$BodyHolder$DDClass" onchange="javascript:setTimeout('__doPostBack(\'ctl00$BodyHolder$DDClass\',\'\')', 0)" id="BodyHolder_DDClass" style="height:27px;width:150px;float:left;"> 
 
    <option value="Select Class">Select Class</option> 
 
    <option value="I BA HEG">I BA HEG</option> 
 
    <option value="I BA HEK">I BA HEK</option> 
 
    <option value="I BA HEP">I BA HEP</option> 
 
</select> 
 

 
<input type="submit" name="ctl00$BodyHolder$Add_New_period_button" value="Add Period" onclick="return addcourse();" id="BodyHolder_Add_New_period_button">

Answer 1

嘗試：

if($("option:selected").hasClass("Select")){ 
    alert("Not valid"); 
    return false; 
}