【原创】javascript获取事件选中的值

function Permissions(){
var a = document.getElementsByName("identity");

for(i=0;i<a.length;i++)
{
if(a[i].checked)
var isinvoice = a[i].value;
}

}

<p>
是否开票：<input id="isinvoice" type="radio" name="identity" value="1" onclick="Permissions()" />已开票<input id="isinvoice" type="radio"
name="identity" value="2" onclick="Permissions()" />未开票</p>