Browsers used by Office Add-ins
Which browser is used depends on:
- The computer’s operating system.
- Whether the add-in is running in Office on the web, Office 365, or non-subscription Office 2013 or later.
The following table shows which browser is used for the various platforms and operating systems.
|OS / Platform||Browser|
|Office on the web||The browser in which Office is opened.|
|Windows / non-subscription Office 2013 or later||Internet Explorer 11|
|Windows 10 ver. < 1903 / Office 365||Internet Explorer 11|
|Windows 10 ver. >= 1903 / Office 365 ver < 16.0.11629||Internet Explorer 11|
|Windows 10 ver. >= 1903 / Office 365 ver >= 16.0.11629||Microsoft Edge*|
* When Microsoft Edge is being used, the Windows 10 Narrator (sometimes called a "screen reader") reads the
<title> tag in the page that opens in the task pane. When Internet Explorer 11 is being used, the Narrator reads the title bar of the task pane, which comes from the
<DisplayName> value in the add-in's manifest.
Troubleshooting Microsoft Edge Issues
Chromium-based Edge is installed on my development computer, but my add-in does not use it
The base browser in Microsoft Edge has changed to Chromium. The older base, called EdgeHTML, is not removed when Chromium-based Edge is installed. Office will still use the EdgeHTML base for add-ins until a build of Office 365 that supports Chromium is installed on the computer. We expect these builds to ship in 2020. They will likely appear in the Insiders channel in the first half of the year.
Scroll bar does not appear in task pane
By default, scroll bars in Microsoft Edge are hidden until hovered over. To ensure that the scroll bar is always visible, the CSS styling that applies to the
<body> element of the pages in the task pane should include the -ms-overflow-style property and it should be set to
When debugging with the Microsoft Edge DevTools, the add-in crashes or reloads
Setting breakpoints in the Microsoft Edge DevTools can cause Office to think that the add-in is hung. It will automatically reload the add-in when this happens. To prevent this, add the following Registry key and value to the development computer:
When the add-in tries to open, get "ADD-IN ERROR We can't open this add-in from the localhost" error
One known cause is that Microsoft Edge requires that localhost be given a loopback exemption on the development computer. Follow the instructions at Cannot open add-in from localhost.