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Decreased rendering performance in Internet Explorer when adjusting zoom level in Quirks mode


The retired, out-of-support Internet Explorer 11 desktop application has been permanently disabled through a Microsoft Edge update on certain versions of Windows 10. For more information, see Internet Explorer 11 desktop app retirement FAQ.

This article provides information about the reduction of web page zoom performance when Quirks mode is enabled in the web browser and provides suggestions.

Original product version:   Internet Explorer 11, Internet Explorer 10, Internet Explorer 9
Original KB number:   2738239


Most web browsers will switch to Quirks Mode if a web page uses non-standard HTML document declaration. Apart from most non-Microsoft web browsers, Internet Explorer uses a Quirks Mode rendering engine, which is not based on a Standards Mode rendering engine. The Quirks Mode rendering engine for Internet Explorer is based on Internet Explorer 5.5. It was first introduced with Internet Explorer 6 for backwards compatibility with legacy web pages.

More information

Quirks Mode is not aware of page zooming, a feature that has been available since Internet Explorer 7. Quirks Mode has not received any performance improvements to maintain backwards compatibility for page zooming. As a result, poor performance may be detected when using page zooming on web pages when using Quirks Mode.

This behavior is by design when Quirks Mode gets used. Recommended to use the most current Internet Explorer standards mode, which is not affected by this page zooming issue.


More information on Internet Explorer document modes can be found at the following locations: