function go3(){
var aaa=document.getElementsByName("send_resource");
for(var i=0;i<aaa.length;i++){
    if(aaa[i].checked==true){
     var b=aaa[i].value
   alert(document.getElementsByName(b)[0].value)
  }
}
}
   <input name="send_resource" type="radio" value="hz" checked>hz
    <input name="hz" value="20" type="hidden">
    <input name="send_resource" type="radio" value="gz">gz
    <input name="gz" value="50" type="hidden">
<INPUT TYPE="button" value="go3" onclick="go3()">