Page Integrity when Zooming
This is a technique for testing:
1.4.4 Resize text: Except for captions and images of text, text can be resized without assistive technology up to 200 percent without loss of content or functionality. (Level AA) How to Meet 1.4.4 | Understanding 1.4.4
Zooming works differently in the various browsers but on the whole the aim is to enlarge all that can be seen on the web site without disturbing the layout as can happen when text sizes are changed. However, this is not always the way things work and ideally checks need to occur across several pages even across one website with several different browsers.
The pictures below are of the BBC web site (May 8th 2009) as zoomed in Internet Explorer, Firefox, Opera first and then with text only zooming in Google Chrome and Safari. However, if you are using a Mac, hold down the ctrl key and scroll up or down to zoom in/out – this zooms in and out on any application not just Safari.
Further comparisons by baekdal.com
Depending on the type of mouse you are using it is possible to test for zooming by using the mouse wheel or Ctrl + and Ctrl - and Ctrl + 0 to return to normal in Internet Explorer and Firefox.
The Web Developer toolbar in Firefox has a resizing menu that also offers different resolutions and a chance to check the window size.