当用户从上一个元素中选择一个选项时，如何显示隐藏的元素

Question

我正在为作业创建表格。 在选择其他问题的值时，如何使新问题出现？ 例如，

<label for="Etype">*What would you like to enrol in?</label>
<select id="Etype" name="Etype">
    <option value="">Select...</option>
    <option value="Camp">Camp</option>
    <option value="Class">Class</option>
</select>
</fieldset>

在选择“班级”之后，在先前询问“班级类型”的问题下方会显示一个先前隐藏的问题。

Answer 1

将其放在您的身体闭合标签之前：

<script>
document.getElementById('Etype').onchange = function() {
    var isSelected = this.options[this.selectedIndex].value == 'Class';
    document.getElementById('hiddenField').style.display = isSelected ? 'block':'none';
};
</script>

假设隐藏元素的ID为“ hiddenField”：

<div id="hiddenField" style="display:none;">
    Place the hidden field, labels, etc. here
</div>

Answer 2

的HTML

<fieldset>
<label for="Etype">*What would you like to enrol in?</label>
       <select id="Etype" onchange="show_hidden(this.value)" name="Etype">
          <option value="">Select...</option>
          <option value="Camp">Camp</option>
          <option value="Class">Class</option>
      </select>

<div id="class">
Type of class : <input type="text" name="class_text" />
</div><!-- #class -->
<div id="camp">
 Type of Camp <input type="text" name="camp_text" />
</div><!-- #camp -->
</fieldset>

的CSS

#class, #camp{display:none;}

Java脚本

function show_hidden(str)
{
   // if first option was selected, hide both the hidden fields
   if(str == '')
   {
      document.getElementById('class').style.display = 'none';
      document.getElementById('camp').style.display = 'none';
   }
   // if class was selected, show the class fields and hide camp fields if visible
   else if(str == 'Class')
   {
      document.getElementById('class').style.display = 'block';
      document.getElementById('camp').style.display = 'none';
   }
   // if camp was selected, show the camp fields and hide class fields if visible
   else if(str == 'Camp')
   {
      document.getElementById('camp').style.display = 'block';
      document.getElementById('class').style.display = 'none';
   }
}

演示