Javascript 选择的索引 onchange 根本不起作用 [英] Javascript selected index onchange doesn't work at all

问题描述

我正在尝试创建一个包含值的选择标记，如果选择了五个值中的两个，另一个选择框将显示在屏幕上.我试过搜索这个，发现人们在哪里使用 javascript 并使用 onchange 事件，但由于某种原因我无法让它工作.如果选择了个人或短期，如果不想将其隐藏，则切换 ID 是我想要显示的 ID.代码如下，提前感谢您的帮助.我没有包含 javascript，因为我把它全部删除了，但我尝试了几种不同的方法，但没有成功.我认为这是我布置表格的方式.

HTML

<td class='txt'><span>&#42;</span>需要覆盖吗?</td><td><select name="ins_type" id='ins_options' onChange="toggle();"><option>选择...</option><option value="Group">团体保险</option><option value="Individual">Individual Insurance</option><option value="Short Term">短期保险</option><option value="Medicare">Medicare</option><option value="Life">人寿保险</option></选择></td><td ><div id='toggle'><span>&#42;</span>多少?<选择名称='申请人' id='申请人' ><option>选择...</option><option value='1'>1</option><option value='2'>2</option><option value='3'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='1'>8</option><option value='9'>9</option><option value='10'>10</option></选择>

</td></tr>

Javascript(我认为这样的东西应该可以工作)

解决方案

您在选择的索引查找中缺少 document - http://jsfiddle.net/VfEyW/

所以代替

[getElementById("ins_options").selectedIndex]

试试

[document.getElementById("ins_options").selectedIndex]

...

更新

要检查 2 个值，您可以这样做

 函数切换() {var val = document.getElementById("ins_options").options[document.getElementById("ins_options").selectedIndex].value;if ( val == "Individual" || val == "Short Term" ) {document.getElementById("toggle").style.display = "none";} 别的 {document.getElementById("toggle").style.display = "block";}}

I am trying to create a select tag that holds values in it and if two out of the five values are selected another select box will show on the screen. I have tried searching for this and found where people are using javascript and using the onchange event but for some reason I cannot get it to work. The toggle id is the one I want to show up if individual or short term is selected if not I want it to be hidden. The code is below and thanks for your help in advance. I didn't include the javascript because I deleted it all but I have tried it a few different ways with no luck. I am thinking it is the way I have the form laid out.

HTML

<tr>                        
   <td class='txt'><span>&#42;</span>Coverage Needed?</td>  
<td>
   <select name="ins_type" id='ins_options' onChange="toggle();">
     <option>Select...</option>                             
     <option value="Group">Group Insurance</option>
     <option value="Individual">Individual Insurance</option>
     <option value="Short Term">Short Term Insurance</option>                                   
     <option value="Medicare">Medicare</option>
     <option value="Life">Life Insurance</option>   
   </select>                
</td>                                   
<td ><div id='toggle'><span>&#42;</span>How Many?
   <select name='applicants' id='applicants' >                                      
      <option>Select...</option>
      <option value='1'>1</option>
      <option value='2'>2</option>
      <option value='3'>3</option>
      <option value='4'>4</option>
      <option value='5'>5</option>
      <option value='6'>6</option>
      <option value='7'>7</option>
      <option value='1'>8</option>
      <option value='9'>9</option>
      <option value='10'>10</option>    
   </select>
  </div>
  </td>             
</tr>

Javascript (I was thinking something like this should work)

<script type="text/javascript">
  function toggle() {
    if (document.getElementById("ins_options").options
    [getElementById("ins_options").selectedIndex].value == "Individual") {
       document.getElementById("toggle").style.display = "none";
    } else {
       document.getElementById("toggle").style.display = "block";
    }
  }
</script> 

解决方案

You're missing document in your selected index lookup - http://jsfiddle.net/VfEyW/

So instead of

[getElementById("ins_options").selectedIndex]

try

[document.getElementById("ins_options").selectedIndex]

...

UPDATE

To check against 2 values you can do this

  function toggle() {
    var val = document.getElementById("ins_options").options[document.getElementById("ins_options").selectedIndex].value;

    if ( val == "Individual" || val == "Short Term" ) {
       document.getElementById("toggle").style.display = "none";
    } else {
       document.getElementById("toggle").style.display = "block";
    }
  }

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