PHP 和 mysql : how can i make selected option stay selected in s Combo after submit

Question

我在 stackoverflow 中搜索，我唯一得到的是类似 this 的东西.我想用这段代码来做

<select class="input_select" name='nombre_compania'><?
    msqlcon_catering(); //which is the function i made that connects to the database
    $query = "SELECT * FROM compania ORDER BY id DESC";
    $result = mysql_query($query);
    while ($r = mysql_fetch_array($result))
    {
      echo "<option value=\"". $r['id'] ."\">". $r['compania_nombre'] ."</option>"; 
    }?>
</select>

当用户选择某个选项时，如果他遗漏了某些内容或输入错误，则在提交表单后保持选中状态。谢谢

Answer 1

<?php
$selected = null;
if(isset($_POST['nombre_compania']))
{
    $selected = $_POST['nombre_compania'];
}

?>

<select class="input_select" name='nombre_compania'><?
    msqlcon_catering(); //which is the function i made that connects to the database
    $query = "SELECT * FROM compania ORDER BY id DESC";
    $result = mysql_query($query);
    while ($r = mysql_fetch_array($result))
    {
      echo "<option value=\"". $r['id'] ."\" ".($selected == $r['id'] ? 'selected=\"selected\"': '').">". $r['compania_nombre'] ."</option>"; 
    }?>
</select>