how to use variables in get

how to use variables in get

Hi there,
 
Is it possible to use variables in place of round1 below? If yes, how?
 
  $.get(sampleNo+'.html?rid='+Math.random(), function(data){
    var dataObj = eval(data)[0];
  
  var thisRoundBids = dataObj.round1.ThisRound;



Thank you.