Dropdownlist验证不起作用

Question

我已经尝试了多次dropdownlist验证， 我的代码是在PHP和HTML中，验证部分不工作，但我已经提到了一些类似的情况下矿。

声明变量

$call_department = $db->escape((int)$_POST['call_department']); //where i declare this variable 

---

HTML文件

<tr><td>Department</td><td><select name='call_department'> 
<option></option> 
<?php $call_dept = $db->get_results("select type_id,type_name from site_types where type=1 order by type_name;"); 
foreach ($call_dept as $dept) 
{?> 
<option value='<?php echo $dept->type_id;?>'><?php echo $dept->type_name; required?></option> 
<?php } ?> 
</select></td></tr> 

---

验证部分：

<?php 
if(isset($_REQUEST['call_department']) && $_REQUEST['call_department'] == '0') { 
echo 'Please select a department.'; 
} 
?> 

Answer 1

1）设置冷杉t选项value="0"这样

<option value="0">select</option> 

2）Required属性应该被设置为选择标记不选项标签<select name='call_department' required>

<select name='call_department' required> 
<option value="0">select</option> 
<?php $call_dept = $db->get_results("select type_id,type_name from site_types where type=1 order by type_name;"); 
foreach ($call_dept as $dept) 
{ 
?> 
<option value='<?php echo $dept->type_id;?>'><?php echo $dept->type_name; ?></option> 

<?php } ?> 
</select>