jquery 获取checkbox,radio,select被选中的值

<code class="language-html"><input type="radio" name="rd" id="rd1" value="1">1
<input type="radio" name="rd" id="rd2" value="2">2
<input type="radio" name="rd" id="rd3" value="3">3</code>

<code class="language-javascript">$('input:radio:checked').val()；
$("input[type='radio']:checked").val();
$("input[name='rd']:checked").val();</code>

<code class="language-html">  <select name="products" id="sel">
    <option value="1">option1</option>
    <option value="2" selected>option2</option>
    <option value="3">option3</option>
    <option value="4">option4</option>
  </select></code>

<code class="language-javascript">$('select#sel option:selected').val();
或者
$('select#sel').find('option:selected').val();</code>

<code class="language-javascript">$('select#seloption:selected').text();
或者
$('select#sel').find('option:selected').text();</code>

<code class="language-javascript">$('select#sel').get(0).selectedIndex;</code>

<code class="language-html"><input type="checkbox" name="ck" value="checkbox1">checkbox1     
<input type="checkbox" name="ck" value="checkbox2" checked>checkbox2     
<input type="checkbox" name="ck" value="checkbox3">checkbox3      </code>

<code class="language-javascript">$("input:checkbox:checked").val() 
或者 
$("input:[type='checkbox']:checked").val(); 
或者 
$("input:[name='ck']:checked").val(); </code>

<code class="language-javascript">$('input:checkbox').each(function() { 
    if ($(this).attr('checked') ==true) { 
        alert($(this).val()); 
    } 
}); </code>