RadioButtonList JS获取其中选定的项

var RadioObject  = document.getElementById("<%=rbltSelectDate.ClientID %>");

var RadioInput  = RadioObject.getElementsByTagName("INPUT");

var BeginDate = document.getElementById("<%=txtBeginYear.ClientID %>");

var EndDate = document.getElementById("<%=txtEndYear.ClientID %>");

var lt = document.getElementById("<%=lbl.ClientID %>");

        

if (RadioInput[2].checked == true)

{

     BeginDate.style.display = '';

     EndDate.style.display = '';

     lt.style.display = '';

}

else

{

     BeginDate.style.display = 'none';

     EndDate.style.display = 'none';   

     lt.style.display = 'none';

}