The article on caching uses HttpWatch to show the difference in performance when the Expires header has been correctly set:

You’ll need to install HttpWatch version 6.1.39 or later if you want to use it with this new version of Firefox.

The HttpWatch Properties window reports this updated version as ‘Firefox 3.5b99′ :

“Members were asked to rate their favorites on http://catalog.codeproject.com/ . The Code Project staff then compiled the highest rated listings, awarding the highest ranked in each product category. It is, indeed, an honor to be ranked highest in your category.”

The results were announced at TechEd 2009 and we were pleased to learn that HttpWatch was the winner in the Debugging category.

Thank you to everyone who voted for HttpWatch.

In this post we wanted to answer some of the questions you may have about Windows Vista 64-bit and the effect it has on the use of Firefox, HttpWatch and Internet Explorer (IE).

How can I tell if a program is running in 32-bit or 64-bit mode?

The Task Manager on Vista 64-bit shows 32-bit tasks with a ‘*32′ after the process name. If there’s no ‘*32′ after the name then it is running in 64-bit mode. This screen shot shows a 32-bit process called page_check running on Vista 64-bit:

Why does IE run in 32-bit mode by default on Vista 64-bit?

Clicking on the launch bar IE icon in Vista 64-bit starts the 32-bit version of IE:

A 64-bit version of IE is available but you have to explicitly select it from the Start menu:

Microsoft has done this because the 64-bit version of IE can only load 64-bit browser extensions and most  extensions, such as the Adobe Flash player, are only available in 32-bit.

Here’s what Adobe says about 64-bit support:

Adobe Flash Player is not supported for playback in a 64-bit browser. However, you can run Flash Player in a 32-bit browser running on a 64-bit operating system.

…

Adobe is working on Flash Player support for 64-bit platforms as part of our ongoing commitment to the cross-platform compatibility of Flash Player. We expect to provide native support for 64-bit platforms in an upcoming release of Flash Player following Flash Player 10.

Without the Flash player, you can’t use sites like YouTube or BBC iPlayer. That’s a non-starter for many web users and the reason why 32-bit IE is the default on Vista 64-bit.

Microsoft is also putting off 64-bit support in Silverlight until other 64-bit extensions are available:

Right now our plan is to run SL in 32-bit mode (and not have a 64-bit native version). This is mostly because other browser plug-ins (and most browsers) don’t support 64-bit yet. We are looking at adding native 64-bit support in the future though.

Can I run Firefox in 64-bit mode on Vista 64?

There’s currently no official build of Firefox for 64-bit Windows as stated in a Mozilla support forum:

There are no releases or nightly builds of 64 bit Firefox for Windows from Mozilla as the earliest release to likely have 64-bit versions is Firefox 4.0. The only option you have is either roll your own or use a third-party build.

There’s little motivation for the browser vendors to go 64-bit because unlike other applications, such as memory hungry video editors or database servers, web browsers will not see significant performance benefits in 64-bit mode and there is also the problem with the lack of 64-bit extensions.

Can I use HttpWatch on Vista 64-bit?

Yes, you can use HttpWatch on Vista 64-bit but it is currently only available in 32-bit. This means that the HttpWatch plug-in can only be used in the 32-bit edition of IE. We will provide 64-bit plug-ins when Adobe, Microsoft and Mozilla provide significant 64-bit support.

The automation interface can be used from 64-bit programs without making any changes so as long as you have HttpWatch version 6.1.32 or later.

In some cases, such as accessing a .hwl file opened with the OpenLog method, you may see reduced performance in a 64-bit program. This is because the 64-bit API support in HttpWatch uses a separate WIN32 process rather than directly loading the API. To avoid this issue make sure that your client program runs 32-bit (see below).

Can I use the HttpWatch version 5.x automation on Vista 64-bit?

This will work, but you will need to ensure that your program runs in 32-bit mode. Otherwise, you will see this error when you attempt to create an instance of the HttpWatch controller object:

Unhandled Exception: System.Runtime.InteropServices.COMException (0x80040154): Retrieving
the COM class factory for component with CLSID {C4CEDB78-2B64-4703-99BE-A037A849D703}
failed due to the following error: 80040154.

If you’re seeing this error with HttpWatch version 6 make sure that you’ve installed version 6.1.32 or later.

How can I get my HttpWatch automation program to run 32-bit?

As mentioned above, you will need to ensure that a program using the HttpWatch automation API runs in 32-bit mode if:

• You are using HttpWatch version 5.x
• You want to improve data access performance on log files that are opened using the OpenLog method.

.Net projects (e.g. C# or VB.Net) have a default configuration setting of ‘Any CPU’. This causes them to automatically run as a  64-bit process on Vista 64-bit. To force them to always run 32-bit you’ll need to change this setting to ‘x86′ in Visual Studio:

Script based programs, such as Javascript or VBScript, that use the Windows Scripting Host will normally run in 64-bit on Vista 64-bit because cscript.exe and wscript.exe are  64-bit programs. You can force the use of 32-bit by using the script programs that are installed in the Windows\SysWow64 directory:

The sample automation code that is installed with HttpWatch version 6.1.32 or later, uses the ‘x86′ setting  in C# projects and includes instructions on how to run the Javascript samples in 32-bit mode.

You can read more about Firefox 3.5 Beta 4 in the Mozilla release notes and a full list of changes to HttpWatch is available on the Version History page and RSS Feed.

In IE 7 and ealier, this dialog would cause annoyance to users but generally didn’t cause any other significant problems. This was because it was worded in such a way that most users would click on the Yes button and allow non-secure content to be downloaded.

However, the wording in the IE 8 version of this dialog has changed:

To download the content a user would now have to click on the No button. As we know, most people using the web only scan text and avoid reading it if at all possible! They will usually go for the Yes button if there is not an OK button.

Some sites are going to find that their secure pages in IE 8 have the following problems:

• Any non-secure HTTP image beacons used for analytics data gathering will often be ignored
• The page may not display or even work correctly if it relies on non-secure images, CSS or Javascript

Therefore, avoiding mixed content on HTTPS pages is even more important now that IE 8 has been released. It often becomes an issue when using third party services such as analytics or Content Delivery Networks (CDN). For example, we avoided the use of Google hosted Ajax libraries on our site until Google added HTTPS support.

As mention in the previous blog post, an IE user you can disable this warning by:

1. Going  to Tools->Internet Options->Security
2. Select the ‘Security’ tab
3. Click the ‘Custom Level’ button
4. In the ‘Miscellaneous’ section change “Display mixed content” to Enable

However, if you are developing a web site you can’t expect your visitors to do this. It is better to fix the cause of the problem so that the warning is not displayed by default in IE 8. The only way to do this warning is to ensure that your HTTPS pages only access embedded resources using the HTTPS protocol. You can do this by following these steps:

1. Use a sniffer like HttpWatch that supports HTTPS and shows files being read from the browser cache. The free Basic Edition is sufficient for this because you only need to see the URLs being accessed.
2. Access the page causing the problem and click No when you see the security warning dialog.
3. Any HTTP resources shown  in the HttpWatch window are the source of the problem; even if they loaded directly from the browser cache and didn’t cause a network round trip:
4. If you don’t initially see any HTTP based resources, try refreshing the page because a non-secure image may have been retrieved from the IE or Firefox image cache

#1 : IE 8 Opens More Connections Per Host Name

As we previously mentioned in Blocked time and IE8, the default number of concurrent connections per host name has been increased in IE 8. In earlier versions of IE only a maximum of two connections would simultaneously download content from a single host name (e.g. www.microsoft.com ). Here’s an example using HttpWatch and IE 7:

The limit of only two active connections would often cause requests to be queued up in IE until a connection became available. In HttpWatch, this is known as the Blocked time and is shown as a gray bar in the time chart.

Increasing the number of active connections to six (the same as Firefox 3.0) allows for much greater concurrently and drastically reduces the amount of blocked time experienced on most web pages:

If you are concerned about your web site’s performance make sure that you also check it in IE 7 as it may be substantially different from IE 8.

#2 : IE 8 Has a New Process Model

IE 8 has a new feature known as Loosely Coupled IE (LCIE) that uses separate instances of the iexplore.exe process to provide enhanced isolation and reliability. The IE frame window and tabs run in a separate processese, so that if one tab crashes you will not lose the whole of your browser session:

IE 8 will even attempt to re-start and re-open an individual tab if a problem occurs. Pop-up windows are treated in a similar way and will placed in separate processes if possible.

One advantage of this model is that it allows tabs for both protected mode and non-protected mode web sites to be loaded into the same top level window. In IE 7, a separate frame window was created if you attempted to open tabs with different protection levels.

Initially, each new tab and pop-up window gets its own process but as the number of tabs grows the number of processes is capped. Once the cap is reached, new tabs will share existing processes with other tabs. By default, the upper limit on the number of processes is based on the amount of physical memory available to Windows.

In previous versions of IE, clicking on the blue ‘e’ icon on the start menu would create a new IE frame window in a separate instance of the iexplore.exe process. In IE 8 this behaviour has been changed in an attempt to reduce the number of processes allocated to IE. It now uses a technique, known as Frame Merging, that creates an IE frame window using the existing IE frame process, if one exists.

If you really want separate IE frame processes you can do this by supplying -nomerge in the IE command line:

iexplore.exe -nomerge

#3 : All IE 8 Tabs, Windows and Pop-ups Belong To The Same Browser Session

Session level cookies used to be maintained at the process level by older versions of IE. This meant that every time you clicked on the IE icon and started a new IE process you also started a new browser session, allowing you to login into multiple accounts (e.g. multiple GMail accounts) simultaneously.

IE 8 does not create a new session for every process, because there could be multiple tabs or pop-up windows in different processes that need to share the same session level cookies. Instead, the browser session is now maintained by the process that contains the main frame window.

The default use of Frame Merging in IE 8 prevents the creation of multiple frame processes, so all windows and tabs will belong to the same session. This is identical to the behavior you get in Firefox using a single default profile.

But what if you need to log into a web site simultaneously using two or more login accounts ?

To create a new session you just have to ensure that a new IE 8 frame process is created. There are two ways to do this:

1. Start IE 8 using the -nomerge command line flag as shown above
2. Use File->New Session. This creates a new frame window process and browser session

#4 : The IE 8 Process Model is Configurable

The IE team has documented a single registry value that controls the new process model. If you create a DWORD value called TabProcGrowth in:

HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main

you can control how many browser processes are used by IE 8:

The three most useful values for this setting are:

1. TabProcGrowth = <absent> - this is the default setting allowing IE 8 to control how many processes are used based on the amount of physical memory installed
2. TabProcGrowth = 0 - a value of zero means use the same process for all tabs, frames and pop-up windows in each browser session. This makes IE 8 behave just like IE 7 on Windows XP. There’s no frame merging and clicking on the IE icon creates a new instance of iexplore.exe in a separate browser session. Protected mode on Vista is not available with this setting because the IE frame and tabs can only operate at different integrity levels if they are in separate processes. This setting may be useful if you are debugging an IE add-on or if you have automated tests that rely on the IE 7 process model.
3. TabProcGrowth = 1 - this means use one process for all the tabs and pop-ups in a browser session and one process for the IE 8 frame window. Frame merging occurs with this setting and protected mode is supported on Vista. You may want to use TabProcGrowth = 1 where you want to keep tabs and pop-ups in one process but still allow the use of protected mode.

Specifying a number greater than 1 sets an upper limited on the maximum number of tab processes to use per frame window process.

#5 : Compatibility Workarounds for IE 8

The new, improved, implementation of standards mode in IE 8 means that some sites that used to work in IE 7 may no longer display correctly. Ideally, every site will update their HTML to make it work correctly in IE 8, but an IE 7 emulation option has been provided as a work-around. It can be triggered by a number of different mechanisms:

1. Microsoft maintains a list of web sites that don’t work well with IE 8 based on feedback from users. The IE 7 emulation mode is automatically enabled for thousands site that are in this list, including popular sites such as amazon.com, ebay.com, google.com and even microsoft.com!
2. A web site developer can indicate that their site requires the compatibility mode by adding this meta tag to their HTML:
   
<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />

   Or by using a response header:

   X-UA-Compatible: IE=EmulateIE7

   Microsoft uses the meta tag on the Microsoft home page and the use of the response header on the MSDN site is shown below in HttpWatch:

   

3. If a user spots a problem they can click on the compatibility mode button in IE 8:
   

   This button doesn’t appear if the site has already specified IE 7 emulation.

Microsoft’s extensive use of IE 7 emulation indicates just how much work is required on a large site to fix up the HTML for IE 8 standards mode and still keep it working with IE 7.

#6 : New Built-in Developer Tools for IE 8

Some excellent developer tools are now built into IE 8. You no longer need to separately install the Web Developer Toolbar used by IE 7. These tools include:

• ‘View Source’ now opens a window with HTML syntax coloring and line numbers instead of the Notepad window used in previous versions.
• A Firebug -like DOM viewer that shows which CSS styles have been applied to an HTML element
• A Javascript Profiler and Console

#7: How to Use HttpWatch with IE 8

The only real difference you will see in HttpWatch with IE 8 is caused by the new process model.

HttpWatch records traffic at the process level. Therefore, in IE 8 it will maintain a separate log for each tab and pop-up process. Generally, this is not an issue as you normally only want to see the traffic for a single tab or window. If you really need to record across multiple tabs or pop-up windows there are two approaches you can use:

1. Change the IE 8 process model so that only one process is used for tabs and windows (i.e. set TabProcGrowth to 0 or 1 ). HttpWatch will then record all the traffic in one log file.
2. If you don’t want to change the process model, you could separately view and save HttpWatch log files from each tab and pop-up window. If a window doesn’t have a toolbar you can open HttpWatch using the Shift+F2 keyboard shortcut

You’ll also find that HttpWatch shortcut keys will not work in the IE 8 location bar or search field. We plan to fix that in a future update, but in the meantime you can work around it by putting the keyboard focus into the web page itself before using the shortcut key.

The Jolt web site describes the purpose of the awards as:

“… recognize the most innovative, trend-making, ahead-of-the-curve products. Jolt-award winners are the software products, books and technologies that developers should be using today.”

The judges are a hand picked group of forward thinking gurus from the software industry who:

“.. define which software development products are ahead of the curve. They honor products that are universally useful, that are simple, yet rich in functionality, or that redefine their product space.”

So, it is a great honor to have HttpWatch considered for and to win such a prestigious award.

• The contents of the Property window can be included on print-outs
• The POST tab now has a size column and an Export button
• Two new setting have been added to Tools->Options->General to give greater control over the use of HttpWatch shortcut keys in the Internet Explorer and Firefox plugins.

A more detailed list of the changes can be viewed on the version history page or the version history RSS feed.