javascript - 脚本中的必需代码不起作用

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How to set HTML5 required attribute in Javascript?
                                
                                    （6个答案）
                                
                        
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脚本中的必需项不起作用

$("#s_postby").attr('required', false); // put the id of the input field that you whant required
$("#s_postby").attr('required', true); // put the id of the input field that you whant required

我在帖子的osclass主题中添加了一些无线电字段！

    <div id="postby" class="property-ads-100">
      <label>
        <span class="required_fields">*</span>
        <?php _e('Posted By', 'ctg_housing'); ?>
      </label>
      <div class="item-post-postby-checkbox columns-0">
        <input  type="radio" name="s_postby" value="owner" id="s_postby0" <?php if(isset($housing['s_postby']) && $housing['s_postby'] =='owner') { echo 'checked="checked"'; }; ?>>
        <label for="s_postby0">
          <?php _e('Owner', 'ctg_housing'); ?>
        </label>
      </div>
      <div class="item-post-postby-checkbox columns-0">
        <input type="radio" name="s_postby" value="agent" id="s_postby1" <?php if(isset($housing['s_postby']) && $housing['s_postby'] =='agent') { echo 'checked="checked"'; }; ?>>
        <label for="s_postby1">
          <?php _e('Agent', 'ctg_housing'); ?>
        </label>
      </div>
      <div class="item-post-postby-checkbox columns-0">
        <input type="radio" name="s_postby" value="broker" id="s_postby2" <?php if(isset($housing['s_postby']) && $housing['s_postby'] =='broker') { echo 'checked="checked"'; }; ?>>
        <label for="s_postby2">
          <?php _e('Broker', 'ctg_housing'); ?>
        </label>
      </div>
      <div class="item-post-postby-checkbox columns-0">
        <input type="radio" name="s_postby" value="agency" id="s_postby3" <?php if(isset($housing['s_postby']) && $housing['s_postby'] =='agency') { echo 'checked="checked"'; }; ?>>
        <label for="s_postby3">
          <?php _e('Agency', 'ctg_housing'); ?>
        </label>
      </div>
    </div>

我将其隐藏在某些类别中（脚本中的必需项不起作用！）为什么？

<script type="text/javascript">
$('#catId').change(function(){
    if( $('#catId').val() == "28" || $('#catId').val() == "29" ||
$('#catId').val() == "30" || $('#catId').val() == "31")
    {
        $("#postby").hide();  // change Posted By with ID you give to the div
    $("#s_postby").attr('required', false); // put the id of the input field that you whant required
    }else
    {
         $("#postby").show(); // change Posted By with ID you give to the div
    $("#s_postby").attr('required', true); // put the id of the input field that you whant required
    }
});
</script>

我现在需要什么来使此无线电字段在显示时是必需的，而在不需要时是隐藏的！当显示并需要时，我需要一条错误消息发布者：此字段为必填项！

希望可以有人帮帮我！

最佳答案

element.required = true;

How to set HTML5 required attribute in Javascript?