javascript for enabling and disabling combo boxes depending value of radiobutton

Thanks for replay,

It is not what i required my code is as follows:

Enable dropdown, disable textbox

    Enable textbox, disable dropdown
   
  
  

   
        Default
   
   
  

   

Javascript is:

function abc()
    {
   
    if (document.form1.rbSelection[0].checked==true)
        {
        document.form1.dropdownlist.disabled=false;
        document.form1.textbox.disabled=true;
        }
    else
        {   
        document.form1.dropdownlist.disabled=true;
        document.form1.textbox.disabled=false;
        }
    }

• My page inherits matster page. and above code is not working.
  

Regards

Rajath

function getChecked()
 {
   if(document.getElementById("RadioButton1").checked==true)
   {
     alert("test");//enabe combo box.
   }
 }