我有四个表，每个表中有多个单选按钮，现在如何使用javaScript获得所选的单选按钮

Question

<div id="tab_2_contents" class="tab_contents">
<div class="table-responsive">
<font style="font-size:large">
<table class="table table-responsive table-striped">
<thead>
1.The instructor set out the course objectives at the begining
</thead>
<tbody>
<tr>
<td>
<label class="label label-success">
<input type="radio" id="radio" value="Poor" name="radio" style="width:20px" checked/>
<span class="lbl padding-8">Poor</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio" value="Fair" name="radio" style="width:20px" />
<span class="lbl padding-8">Fair</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio" value="Average" name="radio" style="width:20px" />
<span class="lbl padding-8">Average</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio" value="Good" name="radio" style="width:20px" />
<span class="lbl padding-8">Good</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio" value="VeryGood" name="radio" style="width:20px" />
<span class="lbl padding-8">VeryGood</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio" value="Excellent" name="radio" style="width:20px" />
<span class="lbl padding-8">Excellent</span>
</label>
</td>
</tr>
</tbody>
</table>
<table class="table table-responsive table-striped">
<thead>
2.The instructor communicated his/her ideas clearly
</thead>
<tbody>
<tr>
<td>
<label class="label label-success">
<input type="radio" id="radio1" value="Poor" name="radio" style="width:20px" />
<span class="lbl padding-8">Poor</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio1" value="Fair" name="radio" style="width:20px" />
<span class="lbl padding-8">Fair</span>
</label>
</td>
<td>
 <label class="label label-success">
<input type="radio" id="radio1" value="Average" name="radio" style="width:20px" />
<span class="lbl padding-8">Average</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio1" value="Good" name="radio" style="width:20px" />
<span class="lbl padding-8">Good</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio1" value="VeryGood" name="radio" style="width:20px" />
<span class="lbl padding-8">VeryGood</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio1" value="Excellent" name="radio" style="width:20px" />
<span class="lbl padding-8">Excellent</span>
</label>
</td>
</tr>
</tbody>
</table>
<table class="table table-responsive table-striped">
<thead>
3.He/She encourages discussion during the lecture
</thead>
<tbody>
<tr>
<td>
<label class="label label-success">
<input type="radio" id="radio2" value="Poor" name="radio" style="width:20px" />
<span class="lbl padding-8">Poor</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio2" value="Fair" name="radio" style="width:20px" />
<span class="lbl padding-8">Fair</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio2" value="Average" name="radio" style="width:20px" />
<span class="lbl padding-8">Average</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio2" value="Good" name="radio" style="width:20px" />
<span class="lbl padding-8">Good</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio2" value="VeryGood" name="radio" style="width:20px" />
<span class="lbl padding-8">VeryGood</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio2" value="Excellent" name="radio" style="width:20px" />
<span class="lbl padding-8">Excellent</span>
</label>
</td>
</tr>
</tbody>
</table>
<table class="table table-responsive table-striped">
<thead>
4.He/She competently answered participant's questions
</thead>
<tbody>
<tr>
<td>
<label class="label label-success">
<input type="radio" id="radio3" value="Poor" name="radio" style="width:20px" />
<span class="lbl padding-8">Poor</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio3" value="Fair" name="radio" style="width:20px" />
<span class="lbl padding-8">Fair</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio3" value="Average" name="radio" style="width:20px" />
<span class="lbl padding-8">Average</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio3" value="Good" name="radio" style="width:20px" />
<span class="lbl padding-8">Good</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio3" value="VeryGood" name="radio" style="width:20px" />
<span class="lbl padding-8">VeryGood</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio3" value="Excellent" name="radio" style="width:20px" />
<span class="lbl padding-8">Excellent</span>
</label>
</td>
</tr>
</tbody>
</table>
<table class="table table-responsive table-striped">

<thead class="header">
5.Overall rating of the instructor

</thead>

<tbody>
<tr>
<td>
<label class="label label-success">
<input type="radio" id="radio4" value="Poor" name="radio" style="width:20px" />
<span class="lbl padding-8">Poor</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio4" value="Fair" name="radio" style="width:20px" />
<span class="lbl padding-8">Fair</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio4" value="Average" name="radio" style="width:20px" />
<span class="lbl padding-8">Average</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio4" value="Good" name="radio" style="width:20px" />
<span class="lbl padding-8">Good</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio4" value="VeryGood" name="radio" style="width:20px" />
<span class="lbl padding-8">VeryGood</span>
</label>
</td>
<td>
<label class="label label-success">
<input type="radio" id="radio4" value="Excellent" name="radio" style="width:20px" />
<span class="lbl padding-8">Excellent</span>
</label>
</td>
</tr>
</tbody>
</table>
<table class="table table-responsive table-striped">
<tbody>
<tr>
<td>
<input type="button" class="btn btn-primary" onclick="javaScript:feedback()" id="feedback" value="Submit"/>
</td>
</tr>
</tbody>
</table>
</font>
</div>

</div>

这是我的javaScript。

function feedback(){
var s = document.getElementById('radio').value;
alert(s);
}

目前，我正在检查哪个按钮被选中，使用警报，但这是无效的，有人可以帮助我哪里出错。在点击按钮，我想得到所有选择的按钮，从所有的table.Here，我试图把反馈页，在我的应用程序中，每个问题将有五个选择，每个选择都有单选按钮附加到它。

Answer 1

使用document.querySelector();

function feedback(){
var x =document.querySelector('input[name="radio"]:checked').value;
alert(x)
}

示例

Answer 2

您可以使用它们的名称作为表单的命名属性来获取集合单选按钮，然后在集合中循环以找到已检查的属性。

​

function getSelected(radios) {
  for (var i=0, iLen=radios.length; i<iLen; i++) {
    if (radios[i].checked) return radios[i].value;
  }
  return '';
}

<form onclick="this.selectedRadioValue.value = getSelected(this.foo)">
  1<input type="radio" name="foo" value="1">
  2<input type="radio" name="foo" value="2">
  3<input type="radio" name="foo" value="3">
  <br>
  Selected: <input type="text" name="selectedRadioValue">
  <input type="reset">
</form>

​

如果希望使用查询选择器接口，则可以使用：

function getSelected() {
  var radio = document.querySelector('input[name=foo]:checked');
  return radio? radio.value : '';
}

请注意，您必须首先检查返回的值，因为如果没有选择收音机，那么querySelector将返回null，并且尝试访问null的值属性将引发错误。

Answer 3

function feedback(){
var check = document.querySelector('input:radio[name="radio"]:checked').value;
alert(check);
}