Get RadioButtonList Value

function getRadioButtonList( ) {
	var radioObj = document.getElementById ( "<%=RadioButtonList1.ClientID %>" );
	var radioList = radioObj.getElementsByTagName ( 'input' );
	for ( var i = 0; i < radioList.length; i++)
	{
		if (radioList[i].checked )
		{
			alert (radioList[i].value );
		}
	}
}