The Tor Browser / file revision

 // target for window.open()

 const KID_URL       = "child-window.html";

 // formats final results

 const SERVER_URL    = "http://jrgm.mcom.com/cgi-bin/window-open-2.0/openreport.pl";

 // let system settle between each window.open

 const OPENER_DELAY  = 1000;   

 // three phases: single open/close; overlapped open/close; open-all/close-all

 var PHASE_ONE     = 10; 

 var PHASE_TWO     = 0; 

 var PHASE_THREE   = 0; 

 // keep this many windows concurrently open during overlapped phase

 var OVERLAP_COUNT = 3;

 // repeat three phases CYCLES times    

 var CYCLES        = 1;  

 // autoclose flag

 var AUTOCLOSE = 1;

 // Chrome url for child windows.

 var KID_CHROME   = null;

 var SAVED_CHROME = null;

 // URL options and correspnding vars.

 const options = [ [ "phase1", "PHASE_ONE", false ],

                   [ "phase2", "PHASE_TWO", false ],

                   [ "phase3", "PHASE_THREE", false ],

                   [ "overlap", "OVERLAP_COUNT", false ],

                   [ "cycles", "CYCLES", false ],

                   [ "chrome", "KID_CHROME", true ],

                   [ "close", "AUTOCLOSE", false ] ];

 // Note: You can attach search options to the url for this file to control

 // any of the options in the array above.  E.g., specifying

 // mozilla -chrome "file:///D|/mozilla/xpfe/test/winopen.xul?phase1=16&close=0"

 // will run this script with PHASE_ONE=16 and AUTOCLOSE=0.

 //

 // On Win32, you must enclose the -chrome option in quotes in order pass funny Win32 shell

 // characters such as '&' or '|'!

 var opts = window.location.search.substring(1).split( '&' );

 for ( opt in opts ) {

     for ( var i in options ) {

         if ( opts[opt].indexOf( options[i][0]+"=" ) == 0 ) {

             var newVal = opts[opt].split( '=' )[ 1 ];

             // wrap with quotes, if required.

             if ( options[i][2] ) {

                 newVal = '"' + newVal + '"';

             }

             eval( options[i][1] + "=" + newVal + ";" );

         }

     }

 }

 var prefs = null;

 if ( KID_CHROME ) {

     // Reset browser.chromeURL so it points to KID_CHROME.

     // This will cause window.open in openWindow to open that chrome.

     netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");

     prefs = Components.classes["@mozilla.org/preferences-service;1"]

               .getService( Components.interfaces.nsIPrefBranch );

     SAVED_CHROME = prefs.getCharPref( "browser.chromeURL" );

     prefs.setCharPref( "browser.chromeURL", KID_CHROME );

 }

 const CYCLE_SIZE    = PHASE_ONE + PHASE_TWO + PHASE_THREE;

 const MAX_INDEX     = CYCLE_SIZE * CYCLES;  // total number of windows to open

 var windowList      = [];   // handles to opened windows

 var startingTimes   = [];   // time that window.open is called

 var openingTimes    = [];   // time that child window took to fire onload

 var closingTimes    = [];   // collect stats for case of closing >1 windows

 var currentIndex    = 0;       

 function childIsOpen(aTime) {

     openingTimes[currentIndex] = aTime - startingTimes[currentIndex];

     updateDisplay(currentIndex, openingTimes[currentIndex]);

     reapWindows(currentIndex);

     currentIndex++;

     if (currentIndex < MAX_INDEX)

         scheduleNextWindow();

     else

         window.setTimeout(reportResults, OPENER_DELAY);

 }

 function updateDisplay(index, time) {

     var formIndex = document.getElementById("formIndex");

     if (formIndex) 

         formIndex.setAttribute("value", index+1);

     var formTime  = document.getElementById("formTime");

     if (formTime) 

         formTime.setAttribute("value", time);

 }

 function scheduleNextWindow() {

     window.setTimeout(openWindow, OPENER_DELAY);

 }

 function closeOneWindow(aIndex) {

     var win = windowList[aIndex];

     // no-op if window is already closed

     if (win && !win.closed) {

 	win.close();

 	windowList[aIndex] = null;

     }

 }    

 function closeAllWindows(aRecordTimeToClose) {

     var timeToClose = (new Date()).getTime();

     var count = 0;

     for (var i = 0; i < windowList.length; i++) {

 	if (windowList[i])

 	    count++;

 	closeOneWindow(i);

     }

     if (aRecordTimeToClose && count > 0) {

         timeToClose = (new Date()).getTime() - timeToClose;

         closingTimes.push(parseInt(timeToClose/count));

     }

 }    

 // close some, none, or all open windows in the list

 function reapWindows() {

     var modIndex = currentIndex % CYCLE_SIZE;

     if (modIndex < PHASE_ONE-1) {

 	// first phase in each "cycle", are single open/close sequences

 	closeOneWindow(currentIndex);

     } 

     else if (PHASE_ONE-1 <= modIndex && modIndex < PHASE_ONE+PHASE_TWO-1) {

 	// next phase in each "cycle", keep N windows concurrently open

 	closeOneWindow(currentIndex - OVERLAP_COUNT);

     }

     else if (modIndex == PHASE_ONE+PHASE_TWO-1) {

 	// end overlapping windows cycle; close all windows

 	closeAllWindows(false);

     }

     else if (PHASE_ONE+PHASE_TWO <= modIndex && modIndex < CYCLE_SIZE-1) {

 	// do nothing; keep adding windows

     }

     else if (modIndex == CYCLE_SIZE-1) {

 	// end open-all/close-all phase; close windows, recording time to close

 	closeAllWindows(true);

     }

 }

 function calcMedian( numbers ) {

     if ( numbers.length == 0 ) {

         return 0;

     } else if ( numbers.length == 1 ) {

         return numbers[0];

     } else if ( numbers.length == 2 ) {

         return ( numbers[0] + numbers[1] ) / 2;

     } else {

         numbers.sort( function (a,b){ return a-b; } );

         var n = Math.floor( numbers.length / 2 );

         return numbers.length % 2 ? numbers[n] : ( numbers[n-1] + numbers[n] ) / 2;

     }

 }

 function reportResults() {

     //XXX need to create a client-side method to do this?

     var opening = openingTimes.join(':'); // times for each window open

     var closing = closingTimes.join(':'); // these are for >1 url, as a group

     //var ua = escape(navigator.userAgent).replace(/\+/g, "%2B"); // + == ' ', on servers

     //var reportURL = SERVER_URL + 

     //    "?opening="    + opening + 

     //    "&closing="    + closing + 

     //    "&maxIndex="   + MAX_INDEX + 

     //    "&cycleSize="  + CYCLE_SIZE + 

 	//"&ua="         + ua;

     //window.open(reportURL, "test-results");

     var avgOpenTime = 0;

     var minOpenTime = 99999;

     var maxOpenTime = 0;

     var medOpenTime = calcMedian( openingTimes.slice(1) );

     // ignore first open

     for (i = 1; i < MAX_INDEX; i++) {

         avgOpenTime += openingTimes[i];

         if ( minOpenTime > openingTimes[i] ) {

             minOpenTime = openingTimes[i];

         }

         if ( maxOpenTime < openingTimes[i] ) {

             maxOpenTime = openingTimes[i];

         }

     }

     avgOpenTime = Math.round(avgOpenTime / (MAX_INDEX - 1));

     dump("openingTimes="+openingTimes.slice(1)+"\n");

     dump("avgOpenTime:" + avgOpenTime + "\n" );

     dump("minOpenTime:" + minOpenTime + "\n" );

     dump("maxOpenTime:" + maxOpenTime + "\n" );

     dump("medOpenTime:" + medOpenTime + "\n" );

     dump("__xulWinOpenTime:" + medOpenTime + "\n");

     // Close the root window, if required.

     if ( AUTOCLOSE ) {

         window.close();

     } else {

         document.getElementById("formTimes").value = openingTimes.slice(1);

         document.getElementById("formAvg").value   = avgOpenTime;

         document.getElementById("formMin").value   = minOpenTime;

         document.getElementById("formMax").value   = maxOpenTime;

         document.getElementById("formMed").value   = medOpenTime;

         document.getElementById("formAgain").setAttribute( "disabled", "false" );

     }

 }

 function tryAgain() {

     document.getElementById("formAgain").setAttribute( "disabled", "true" );

     windowList      = [];

     startingTimes   = [];

     openingTimes    = [];

     closingTimes    = [];

     currentIndex    = 0;       

     openWindow();

 }

 function restoreChromeURL() {

     // Restore browser.chromeURL pref.

     if ( KID_CHROME && SAVED_CHROME.length ) {

         netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");

         prefs.setCharPref( "browser.chromeURL", SAVED_CHROME );

     }

 }

 function openWindow() {

     startingTimes[currentIndex] = (new Date()).getTime();

     var path   = window.location.pathname.substring( 0, window.location.pathname.lastIndexOf('/') );

     var url    = window.location.protocol + "//" + 

                  window.location.hostname + path + "/" +

                  KID_URL;

     windowList[currentIndex] = window.open(url, currentIndex);

 }