Diff-IE Add-on for Internet Explorer

Established: October 4, 2010

Diff-IE tracks changes to pages you visit on the Web and shows you what’s changed since the last time you visited.

Diff-IE is a prototype Internet Explorer Add-on that:

  • Highlights the changes to a webpage since the last time you visited it.
  • Enables you to view—and compare—previously cached versions of a page.

When changes are made obvious, especially the subtle and unexpected ones, you get a whole lot more out of the webpages you visit.

Screenshot of Diff-IE highlighting changes to the Bing News page

  • Diff-IE Examples

    Web pages change in a variety of ways. We’ve provided some screenshots of changes that Diff-IE identified which might have otherwise gone unnoticed. Do you have a great example? Send it to us at diffiefb@microsoft.com.

    Find changes in long lists of text

    It can be hard to see changes in long lists of text, but Diff-IE identifies these automatically.

    Screenshot of a personal home page with new content in a long list highlighted

    Track price changes

    We rarely remember prices, but Diff-IE does. Here, the prices of these HP workstations dropped.

    Screenshot of an HP product comparison page showing changed prices highlighted in yellow.

    See new or different search results

    Search results can change in may ways — ranking, snippets, titles, and ads can all change.

    Screenshot of a Bing search results page with new content highlighted in yellow

    Quickly find forum activity

    At a glance, Diff-IE shows which forum threads are active.

    Screenshot of a forum with a circular callout showing the that the numbers of posts in several forums have changed.

  • Once installed, you should see the Diff-IE toolbar in Internet Explorer:

    DiffIE toolbar with controls labeled

    Moving from left to right, the elements of the toolbar are:

    Document icon with green check mark

     Diff toggle button

    This button turns diff highlighting on or off for the current tab. The button has 2 states – show diffs (green tick) and hide diffs (red X). When there are a large number of page changes the visual effect can be overwhelming, so in such cases you can quickly toggle the button to hide the diffs.

    You can control the threshold for the amount of diffs (as a percentage of page content) above which diffs will not be initially highlighted using the “General” tab of the “Settings” dialog. If the threshold is exceeded, then the toggle button is automatically set to the “hide diffs” state. If you wish to see all the diffs, just toggle the button to the “show diffs” state. Note that the threshold does not apply if you subsequently change the compared-to version in the “Compare-to” list.

    Globe icon with red X mark

     Ignore site button

    Not all sites benefit from Diff-IE. For such sites you can make Diff-IE ignore all the pages of that site by simply clicking this button. When you click this button, all cached data for all pages you have visited on this site will be deleted. You can “un-ignore” a site from the “Ignored sites” tab of the “Settings” dialog.

     Compare-to list

    Lists Diff-IE’s previously cached versions of the current page, if any. Each time you visit the page, Diff-IE will cache meta data for it. The maximum history length (the maximum number of previously cached versions) is 5 by default, but can be configured on the “Cache” tab of the “Settings” dialog. Note that not all of your prior visits to a page may appear in the list due to the history limit.

    green arrow

     Load page button

    Loads the previously cached page (in JPG format) corresponding to the selected entry in the “Compare to” list. The JPG is loaded in a new tab. Note that page content caching must be turned on to use this feature. By default page content caching is turned off. To turn it on, go to the “General” tab of the “Settings” dialog.

    icon showing two documents and a magnifying glass

     Side-by-side compare button

    Opens the “Side-by-Side Compare” dialog. This feature requires page content caching (using images) to be turned on and there must also be at least one previous version to compare to. The dialog shows the current version on the left and the previous version on the right (as identified by labels in the upper left-hand corner of each pane). You can drag the image (or use the scrollbars) in either pane to change the visible region of the two pages, which move in tandem. The identifying labels disappear once you change the visible region. Note that you can only compare the current version of the page with a previous version, you cannot compare two previous versions.

    Icon of tools

     Settings button

    Opens the “Settings” dialog (see below). Note that these settings are global to all instances of Diff-IE.

  • General tab

    Enable Diff-IE

    Rather than completely disabling the Diff-IE add-on (via IE), you can quickly disable almost all Diff-IE functionality by unchecking this box. If you think that Diff-IE is causing a problem with your browser, try unchecking this box and see if you can still reproduce the problem.

    Enable Activity Logging

    Use this to opt-in (checked) or opt-out (unchecked) from the Diff-IE user study. If you participate in the study your interactions with Diff-IE, including the non-HTTPS URLs that you visit (but not the content), will be logged on an internal MSR server for analysis. See “Browsing History” in the Data Privacy section for more details.

    Diff-IE Highlighting

    There are two aspects of diff highlighting you can configure: the highlight color, and the limit (threshold) of the amount of change on a page above which diffs are not [initially] shown.

    To change the highlight color, click on either the color bar itself or the “Change” button. This will open the “Color” dialog from which you can select one of the basic or custom colors. You can even create your own colors by clicking the “Define Custom Color >>” button. If you change the highlight color, the current page will be re-highlighted in the new color when the “Settings” dialog closes.

    To change the threshold, either type a value from 0 to 100 in the box, or use the up/down cursor keys, or click the small up/down arrow buttons. The goal of the threshold is to prevent an excessive amount of highlighting on a page that has changed significantly since the last time you visited it, since the highlighting tends to lose its value in such cases. The default setting is 50%. If the amount of change exceeds the threshold, the status area will report “Too many diffs to show” when the page loads and the “Diff toggle” button will be set to the “hide diffs” state. If you still want to see the diffs, just toggle the button to the “show diffs” state.

    Page Content Caching

    If you want to be able to view previous versions of the pages you have visited (rather than just the diffs in the current version), or if you want to use the “Side-by-side compare” feature, then you will need to turn on page content caching, which is off by default. Page content is cached in JPG image format.

    If you turn on page content caching you can specify whether you want the image to be of the entire page by checking the “Capture complete page” option. If this option is unchecked, only the initially visible top portion of the page will be captured (which is faster and consumes less disk space). You can also specify the quality of the captured image : Low (the default), Medium, or High. The better the quality the more disk space each image will consume (the relative size ratios for the 3 qualities are approximately 1 : 1.4 : 4.3, so if the image were 500KB at ‘Low’ quality it would be 2.15MB at ‘High’ quality). Cached JPG files are subject to the same history limit as the cached meta data.

    Even when page content caching is enabled, Diff-IE will never cache content from HTTPS (secure) pages.

    Ignored Sites tab

    Ignored site controls

    The list shows the sites that Diff-IE ignores. Each site is expressed as a URL pattern which typically consists of the domain name followed by the * wildcard character (meaning 0 or more additional characters). Without the trailing wildcard character the URL would need to match exactly in order to be ignored. URL patterns are added to the list either by pressing the “Ignore site” button on the toolbar, or by clicking the “Add” button on the “Ignored Sites” tab. When a URL pattern is added, all cached data is deleted for the previously visited pages that match the pattern. To remove a URL pattern, click the “Remove” button [note that multi-select is not supported]. As an aid to easier removal of an ignored site, the URL pattern (if any) that matches the current page is always automatically highlighted as the initial selection.

    Ignore auto-refresh visits

    Many web pages automatically reload themselves periodically in the browser. Since such a “visit” to the page is not initiated by you  and so you will likely not have viewed the contents of the refreshed page — it generally makes sense to have Diff-IE ignore such  visitations so that they don’t show up in the page visitation history. For these reasons this option is on (checked) by default, and it is strongly recommended that you leave it on.

    Cache tab

    Maximum number of page versions

    This controls the length of the visitation history for a given page. The default is 5, meaning that meta data (and page content, if you have enabled it) will be cached for [up to] your 5 previous visits to a page.

    Current cache size

    Shows how much disk space (in megabytes) Diff-IE’s cache is currently consumes. The cache has a fixed upper limit of 1 GB which is enforced using first-in/first-out ordering. Because of the fixed upper limit it is recommended that you do not set “Maximum number of page versions” too high since – depending on visitation patterns – this may limit the total number of pages for which a useful cache is retained.

    Cached URLs

    This list shows all the URLs that are currently in the Diff-IE cache. You can remove cached data for one or more URLs by selecting them and clicking the “Remove” button. To clear the entire cache, click the “Remove All” button. As an aid to easier removal of cached data, the URL for the current page is always automatically highlighted as the initial selection.

    You can also specify whether you want POST data to be used to distinguish visits to a particular URL by selecting the URL [multi-select is not supported] and checking the “Use POST data to distinguish visits to the selected URL” option. This can be useful when the same URL can display different content based on data that it POSTs back to itself (eg. for a page that implements a paging scheme).

    Clear cache when IE history is deleted

    If you would like the Diff-IE cache to be cleared (emptied) whenever the Internet Explorer history is deleted, then check this option (which is on by default). Note that deleting the IE history is a separate action from deleting the Temporary Internet Files, so on the “Delete Browsing History” IE dialog you would need to either click the “Delete history” or “Delete all” buttons (in IE7) or check the “History” checkbox (on IE8 and IE9).

    About tab

    Show debug console

    This is a debugging/testing feature. It is strongly recommended that you leave this option unchecked. When checked, a console (text) window will open that displays trace messages as Diff-IE executes. The messages are useful when trying to investigate problems with Diff-IE. There is one console window per IE7 app instance. On IE8 and IE9 there may be as many as one console window per new tab opened (per application instance), and because of this potential proliferation you will receive a warning on IE8 and IE9 when turning this option on.

  • Internet Explorer 9 logo

    Important notes for users with Internet Explorer 9

    Internet Explorer 9 made important changes in the way browser add-ons are used.To use Diff-IE with Internet Explorer 9, you need to follow the instructions below:

    1. When prompted, click the Enable button.

    2. The Diff-IE toolbar will appear. However, you must close and re-open your browser to get Diff-IE to work properly.

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Susan Dumais

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Jaime Teevan

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