// this is a custom function that simplifies creating an ajax object

function(url, complete, form, params) {
  params = params ? $H(params).toQueryString() : '';
  if (!complete) complete = function(r){};
  if (form)      params   = Form.serialize(form) + '&' + params;
  new Ajax.Request(url, 
    { asynchronous:true,
      evalScripts:true, 
      onComplete: function(r) { complete(r.responseText); },
      parameters:params
    });
}

Firefox doesn't do a lot of simultaneous AJAX (or any kind of HTTP) requests. IE caps it at 2, too. This will allow you to test your XHR overload scripts, or just load pages faster in general.

1. Go to "about:config"
2. Find and edit the following
* network.http.pipelining=false
* network.http.pipelining.maxrequests=4
* network.http.proxy.pipeline=false
3. Make the false's true; I set my maxrequests at 20

// description of your code here

function simpletogglediv(whichLayer)
{
         var theElementStyle = document.getElementById(whichLayer); 

        if(theElementStyle.style.display == "block")
        { 
                theElementStyle.style.display = "none";  
                 
        }
        else
        { 
                theElementStyle.style.display = "block"; 
        }
}