document.getElementById is null or not an object

Question

Hi Every one

i created dynamic radio button and i add OnClick event on that and i write java script for enable and  disable the button depending upon some status the event is firing from the radio button and i able to check the status when i try to enable or disable the button i am getting the error document.getelementById is null or not an object i will show you the code which is am using

 function RadioEvent(Status,Button)
    {
//       var Button1='<%=btnAccept.ClientID %>';
//       aler(document.getElementById(Button1).Text);
       if(Status=="Request Accepted")
       {
       document.getElementById(Button).Enabled = true;
//            document.getElementById('btnAccept').disabled=true;
       //document.getElementById(Button1).setAttribute('Enabled','true');
     
        //document.getElementById(Button).disabled = true;
           //alert(Status);
            //document.getElementById('btnDecline').Enabled=false;
        //document.getElementById('btnAccept').Enabled = true;
       }
       else
       document.form1.btnDecline.Enable=true;
       //document.getElementById(Button1).removeAttribute('Enabled');
        //document.getElementById(btnDecline).disabled = false;
      
    }

the above is my java script and i am calling event like this

 MyRadioButton.Attributes.Add("onclick", "RadioEvent('" + Status + "','btnDecline');");

please correct me where i am doing mistake