如何使动态下拉列表中的选定值保持选中状态

How to make the selected values in a dynamic drop down lists remain selected?

本文关键字：状态 何使 动态 下拉列表      更新时间：2023-09-26

我有5个下拉列表和一个提交按钮。下拉列表的每个内容都依赖于前一个下拉列表的选择值。我想确保每个下拉列表的选定值保持选中，即使在提交按钮被点击后。有人能帮我一下吗?我看到一个网站，但做的是在ASP。. NET，我更喜欢用PHP, javascript

<script type="text/javascript">
function changeSelect(lang, num, valueElement, nameSelect, nameSpan, dataSup, endId){
    var boxName =  document.getElementById(nameSelect);
    var hackIeSpan =  document.getElementById(nameSpan);
    var contentOption = $.ajax({
          url: "select.php",
          global: false,
          type: "POST",
          data: {
                 lang : lang,
                 num : num,
                 select : valueElement,
                 dataSup : dataSup,
                 endId : endId
             },
          dataType: "html",
          async:false,
          success: function(msg){
        }
       }
    ).responseText;
    hackIeSpan.innerHTML = contentOption;
}


<form id="searchForm" method="post" action="search.php?search&page=0&lang=<?php echo $lang; ?>">
            <fieldset>
                <select name="sort" onchange="changeSelect('<?php echo $lang; ?>', 1, this.value, 'type_list', 'hackIeType', 'null', 'null'); return true;">
                    <option value="0"><?php echo trad('SEARCH_01', $lang); ?></option>
                    <option value="Rental"><?php echo trad('SEARCH_01a', $lang); ?></option>
                    <option value="Sale"><?php echo trad('SEARCH_01b', $lang); ?></option>
                </select>
                <span id="hackIeType">
                    <select name="type_list">
                        <option value="0"><?php echo trad('SEARCH_04', $lang); ?> ...</option>
                    </select>
                </span>

.......

<span id="hackIeSleeps">
                    <select name="bedrooms">
                        <option value="0"><?php echo trad('SEARCH_05', $lang); ?> ...</option>
                    </select>
                </span>
                <span id="spanEndId">
                    <input id="endId" name="endId" type="hidden" value="" /> 
                </span>
                <input id="submit_search_home" type="submit" value="<?php echo trad('BTNSEARCH', $lang); ?>" />
            </fieldset>

当您按下提交按钮时会发生什么?你最终会回到同一页吗?您只需要根据$_POST中发送的值为所需选项提供selected="selected"属性。

作为一个例子(这可能不适合你，取决于当你按下提交时到底发生了什么):

<form id="searchForm" method="post" action="search.php?search&page=0&lang=<?php echo $lang; ?>">
  <fieldset>
    <select name="sort" onchange="changeSelect('<?php echo $lang; ?>', 1, this.value, 'type_list', 'hackIeType', 'null', 'null'); return true;">
      <option value="0"<?php if ($_POST['name'] === '0') echo ' selected="selected"'; ?>><?php echo trad('SEARCH_01', $lang); ?></option>
      <option value="Rental"<?php if ($_POST['name'] == 'Rental') echo ' selected="selected"'; ?>><?php echo trad('SEARCH_01a', $lang); ?></option>
      <option value="Sale"<?php if ($_POST['name'] == 'Sale') echo ' selected="selected"'; ?>><?php echo trad('SEARCH_01b', $lang); ?></option>
    </select>
    <span id="hackIeType">
<?php
  if ($_POST['name'] === '0') {
   // The first select value is default, so we can just output a standard select
   // to be populated by AJAX
?>
      <select name="type_list">
        <option value="0"><?php echo trad('SEARCH_04', $lang); ?> ...</option>
      </select>
<?php
  } else {
   // The first select is populated, so copy the logic that generates your second
   // select from 'select.php' and put it here, then output it
  }
?>
   </span>

.......

    <span id="hackIeSleeps">
<?php
  if ($_POST['type_list'] === '0') {
   // The second select value is default, so we can just output a standard select
   // to be populated by AJAX
?>
      <select name="bedrooms">
        <option value="0"><?php echo trad('SEARCH_05', $lang); ?> ...</option>
      </select>
<?php
  } else {
   // The second select is populated, so copy the logic that generates your third
   // select from 'select.php' and put it here, then output it
  }
?>
    </span>
    <span id="spanEndId">
      <input id="endId" name="endId" type="hidden" value="" /> 
    </span>
    <input id="submit_search_home" type="submit" value="<?php echo trad('BTNSEARCH', $lang); ?>" />
  </fieldset>
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