关于下拉选择单选按钮时选中的项目被选中

Question

我有一个名为reg.php的表单，它的动作是reg.php，我希望选中的下拉值在点击提交时保持选中，我有这样做远远如下

我已经检查过帐的问题所作，但我不能用我的代码匹配它

<?php 
if($_POST['registerbtn']){ 
$selected_value = $_POST['selectID']; 
$query = mysql_query("SELECT linecard_name FROM selection WHERE select_id = '$selected_value'"); 
$rows=mysql_fetch_assoc($query); 
$linecard_name= $rows['linecard_name']; 
$sql = "SELECT select_id, linecard_name FROM selection " . "ORDER BY linecard_name"; 
$rs = mysql_query($sql); 

while($rownw = mysql_fetch_array($rs)){ 
if( $rownw['linecard_name'] == $linecard_name) { 
$options = "<option selected =selected value=".$rownw['select_id']."> " .$rownw['linecard_name']. " </option> "; 
} 
} 
} 

require("./connect.php"); 
$sql = "SELECT select_id, linecard_name FROM selection ". "ORDER BY linecard_name"; 
$rs = mysql_query($sql); 
while($rownw = mysql_fetch_array($rs)){ 
$options .= "<option value = ".$rownw['select_id']." > ".$rownw['linecard_name']. " </option> "; 
} 
mysql_close() ; 

$form = "<form action='./reg.php' method='post'> 
<table> 
<tr> 
<td> </td> 
<td> <font color='red'> $errormsg </font> </td> 
</tr> 

<tr> 
<td> Select Linecard </td> 
<td> <Select name='selectID' > <option value = '0'> Select from here </option> $options </select></td> 
</tr> 

<tr> 
<td > <input type='submit' name='registerbtn' value='Register' /> </td> 
</tr> 
</table> 
echo $form; 

的select语句之前注册按钮被点击是从数据库填充下拉列表， 我只想要选择的项目保持选择，当用户完成特定的选择和r egister按钮被点击，在这种情况下 我的代码再次，但现在填充的下拉与用户选择的项目作为选择，但不清除填充在下拉列表中即以前的项目被点击注册按钮之前， 请帮

Answer 1

我发现它的干净与变量做，就像这样：

while($rownw = mysql_fetch_array($rs)){ 
    $selected = ''; 
    if ($rownw['select_id'] == $selected_value){ 
    $selected = 'selected="selected"'; 
    } 
    $options .= "<option value = ".$rownw['select_id']." $selected > ".$rownw['linecard_name']. " </option> "; 
}