页面加载时重新加载下拉菜单

Question

我有一个html表单，我一直使用它来发布到php表单，这将保存发布的数据到数据库中。现在，当我单击编辑时，我正在将数据重新加载到表单中，这对文本字段很有效，因为我可以使用

value="<?php echo $somefield ?>" 

问题是我不确定如何重新选择我的下拉菜单。菜单看起来像这样，用于选择一个类别，但当页面重新加载时，什么都不会发生，下拉菜单也不会重新加载。

    <select name="category" id="category">
    <option>- Select A Category -</option>
      <optgroup label="Tractors">
      <option value="Tractor">Tractor</option>
      <option value="Compact">Compact</option>
    <option value="Forklift">Forklift</option>
    <option value="Load All">Load All</option>
    <option value="Loader">Loader</option>
    <option value="Maniscopic">Maniscopic</option>
    <option value="Masted">Masted</option>
    <option value="Piviot">Piviot</option>
    <option value="Telescopic">Telescopic</option>
    <option value="UTV">UTV</option>
      </optgroup>
      <optgroup label="Machinery">
      <option value="Attachments">Attachments</option>
      <option value="Bale Handling">Bale Handling</option>
      <option value="Cultivation Equipment">Cultivation Equipment</option>
      <option value="Drills">Drills</option>
      <option value="Feeders">Feeders</option>
      <option value="Fertlizer Spreaders">Fertlizer Spreaders</option>
      <option value="Grass Harrows">Grass Harrows</option>
      <option value="Grassland Equipment">Grassland Equipment</option>
      <option value="Hedge Cutters">Hedge Cutters</option>
      <option value="Mowers">Mowers</option>
      <option value="Muck Spreaders ">Muck Spreaders </option>
      <option value="Ploughs">Ploughs</option>
      <option value="Post Hammers">Post Hammers</option>
      <option value="Power Harrows">Power Harrows</option>
      <option value="Rakes">Rakes</option>
      <option value="Rolls">Rolls</option>
      <option value="Rotovators">Rotovators</option>
      <option value="Shredders">Shredders</option>
      <option value="Splitters">Splitters</option>
      <option value="Sprayers">Sprayers</option>
      <option value="Spreaders">Spreaders</option>
      <option value="Tankers">Tankers</option>
      <option value="Tedders">Tedders</option>
      <option value="Toppers">Toppers</option>
      <option value="Trailers">Trailers</option>
      <option value="Wrappers">Wrappers</option>

      </optgroup>
      <optgroup label="Forklifts">
      </optgroup>
    </select>

Answer 1

<?php

  echo '<select>';
  foreach( $names as $name )
    echo '<option value="'.$name.'" '.($name==$selected?' selected="selected"':'').'>'.$name.'</option>'

  echo '</select>';

?>

Answer 2

在构建列表时，所选选项应将属性selected=设置为“selected”。