爲下拉菜單設置錯誤消息

Question

是否可以爲下拉菜單設置錯誤消息？

在第一頁上，我有一個下拉菜單，用戶可以選擇任意組合，然後單擊提交。

在第二頁上，我具有相同的下拉菜單，如果用戶沒有選擇相同的組合，則會顯示一些錯誤。

<select id="men" class="select_class1" name="subselector" style="display:none" > 
 
    <option value="">Choose an item</option> 
 
    <option value="tsm">T-Shirt</option> 
 
    <option value="lsm">long sleeve</option> 
 
    <option value="tankm">Tank Top</option> 
 
</select> 
 
<select id="color" class="select_class1" name="subselector" style="display:none" > 
 
    <option value="">Choose an item</option> 
 
    <option value="blue">blue</option> 
 
    <option value="red">red</option> 
 
    <option value="black">black</option> 
 
</select>

Answer 1

是。您可以acheive，隨着PHP組合和JQUERY

比方說，這是你的第一頁

<form action="secondPage.php" method="post"> 
    <select id="men" class="select_class1" name="subselector"> 
     <option value="">Choose an Item</option> 
     <option value="tsm">T-Shirt</option> 
     <option value="lsm">Long Sleeve</option> 
     <option value="tankm">Tank Top</option> 
    </select> 
    <input type="submit" value="submit" /> 
</form> 

那麼這將是您的secondPage.php

<?php 
    $subselector = $_POST['subselector']; 
?> 
<form action="anotherPage.php" method="post"> 
    <select id="men" class="select_class1" name="subselector"> 
     <option value="">Choose an Item</option> 
     <option value="tsm">T-Shirt</option> 
     <option value="lsm">Long Sleeve</option> 
     <option value="tankm">Tank Top</option> 
    </select> 
    <input type="submit" value="submit" /> 
</form> 

<!-- Now using jQuery to prevent the form from submitting if only the previous selected value doesn't correspond with the present selected value --> 
<!-- don't forget to include your jQuery library here --> 

<script> 
    $('form').submit(function(e){ 
     prevSelVal = "<?php echo $subselector; ?>"; 
     presentVal = $('select').val(); 
     if(prevSelVal !== presentVal){ 
      e.preventDefault(); 
      alert('Your Previous Selected Value must Correspond With Your Present Selected Value'); 
     } 
    }); 
</script>