jquery – 当单选按钮未选中时进行监视

我有一个应用程序，当一个特定的单选按钮被选中时显示一个div，然后当单选按钮未被选择时隐藏该div。问题是，附加到单选按钮的更改事件只有在单选按钮被选中时才会被调用，而不是当选中另一个(取消选中前一个)时。我当前的代码如下：

<form name="newreport" action="#buildurl('report.filters')#" method="post">
    <dl class="oneColumn">
        <dt class="first"><label for="txt_name">Name</label></dt>
        <dd><input type="text" name="name" id="txt_name" class="text" /></dd>
        <dt><strong>Type</strong></dt>
        <dt><input type="radio" name="type" id="rdo_list" value="list" checked="checked" /><label for="rdo_type" style="display:inline;">List</label></dt>
        <dd>List a group of records</dd>
        <dt><input type="radio" name="type" id="rdo_fields" value="fields" /><label for="rdo_fields" style="display:inline;">Field Breakdown</label></dt>
        <dd>Breaks down distinct field values for comparison</dd>
        <dt><input type="radio" name="type" id="rdo_history" value="history" /><label for="rdo_history" style="display:inline;">Historical Comparison</label></dt>
        <dd>Provides record changes over a group of years for growth comparisons</dd>
        <dt><input type="radio" name="type" id="rdo_breakdown" value="breakdown" /><label for="rdo_breakdown" style="display:inline;">Student Breakdown</label></dt>
        <dd>Breaks down students by school,district or grade</dd>
        <div class="reportyear">
            <dt><label for="txt_year">Year to Report</label></dt>
            <dd><input type="text" name="year" id="txt_year" class="text" value="#year(Rc.yearstart)#" /></dd>
        </div>
        <div class="date-spans" style="display:none;">
            <dt><label for="txt_yearstart">Year Start</label></dt>
            <dd><input type="text" name="yearstart" id="txt_yearstart" class="text" value="#evaluate(year(Rc.yearstart)-5)#" /></dd>
            <dt><label for="txt_yearend">Year End</label></dt>
            <dd><input type="text" name="yearend" id="txt_yearend" class="text" value="#year(Rc.yearstart)#" /></dd>
        </div>
    </dl>
</form>


<script type="text/javascript">
    $(function(){
        $('##rdo_history').change(function(e){
            var isChecked = $(this).attr(checked);
            var $datespan = $('form .date-spans');
            var $year = $('form .reportyear');

            if(isChecked){
                $year.css({display:'none'});
                $datespan.fadeIn('fast');
            }else{
                $datespan.css({display:'none'});
                $year.fadeIn('fast');
            }
        });
    });
</script>

它看起来像一个非常简单的脚本，但事件只能在检查事件，而不是uncheck事件。任何人都可以告诉我为什么？

$("input[name='type']").change(function(e){
    if($(this).val() == 'history') {
        $year.css({display:'none'});
        $datespan.fadeIn('fast');
    } else {
        $datespan.css({display:'none'});
        $year.fadeIn('fast');
    }

});