# qooxdoo

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# Internet Explorer specific settings

This page describes all settings which are used/implemented by qooxdoo to workaround/solve IE-specific issues.

## Document Mode in IE8

qooxdoo uses Internet Explorer 8 standard mode as the default for all generated applications. This is achieved by setting a XHTML 1.2 Doctype to all index.html files provided by the framework.

## Using alpha-transparent PNGs

IE7 and IE8 have built-in support for loading alpha-transparent PNGs. qooxdoo however does use the AlphaImageLoader for all IE versions whenever a PNG image has to be loaded. This has several reasons:

- Performance issues in IE8 - native alpha PNG support is slower when running IE8 standards mode
- Rendering bug in IE - reported at Bug #1287

## URL-Rewriting under HTTPS

Every IE version does show a Mixed Content warning whenever a resource (image, script, etc.) is loaded with a regular HTTP request when the containing page runs under HTTPS. However, this useful warning is also appearing in situations it is not acceptable, e.g. for relative paths like ./path/to/my/resource. In order to solve these issues every URL of a resource managed by qooxdoo is rewritten in IE under HTTPS to an absolute URL to prevent the warning. See Bug #2427 for more details.