When an element's foreground and background colour combination fail either the luminosity contrast ratio or the colour contrast algorithm suggested by AERT, the whole row is coloured yellow. This saves listing things like the li element more times than necessary. Duplicate elements that share the same parents with the same class and id attribute values are only listed once. In the case of an element that contains other elements but also has text content, then the element is analysed. For example, if the colour contrast for an li element is poor, but all li's for a particular list only contained anchor elements, then only the anchor elements are analysed. This avoids listing contrasts that could fail on colour contrast, but only contain elements where the styles are overridden and pass. Only elements that contain text are listed. Each element is also listed with its parent elements, and class and id attribute values when specified to make it easier to locate the elements. The Colour Contrast Analyser Firefox extension lists colour combinations used in the document in a table that summarises the foreground colour, background colour, luminosity contrast ratio, and the colour difference and brightness difference used in the algorithm suggested in the 26th of April 2000 working draft for Accessibility Evaluation and Repair Tools ( AERT). If you evaluate websites for colour contrast, this extension will be useful for saving you time, and also take out the guesswork required to determine which colours to test. I've written a Firefox extension that reveals the colour contrast of all elements in the DOM. The problem with colour contrast analysers is that they don't automatically go through all of the possible colour combinations in a document instead, it requires a judgement call by the person evaluating the page to decide whether colour combinations look like they may be problematic, and then to enter those colours into a colour contrast analyser. Determining the colour contrast between foreground and background colours is a time consuming task, but is greatly aided by colour contrast analysers.
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