var haha;

function ajaxfunction(){
   var request;
   var returning;

   try {
      request = new XMLHttpRequest();
   } catch(e){
      try {
         request = new ActiveXObject("Msxml2.XMLHTTP");
      } catch(e){
         try {
            request = new ActiveXObject("Microsoft.XMLHTTP");
         } catch(e){
         }
      }
   }

   request.onreadystatechange = function(){
      if(request.readyState == 4){
         haha = request.responseText;
      }
   }

   request.open("GET", "pick.php", true);
   request.send(null);
}

ajaxfunction();

if(haha == "yay"){
   alert("This"); // this is an example, don't know what to use instead (probably another function soon
}