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Quirks Mode Statistics

This page shows proportion of pages using quirks mode for sites submitted to this service.

Quirks Mode Pages

Graph: about 30% of pages render in quirks mode

Percentage of pages with quirks mode DOCTYPEs.

What is Quirks Mode?

Older web pages don't usually meet W3C standards, so browsers have to display them using "best effort". This often contradicts W3C standards, so modern browsers display pages using two methods:

Standards Mode - documents with an HTML 4.01 or XHTML DOCTYPE are displayed in standards mode. Standard mode pages tend to look quite similar between different browsers (but not always identical).
Quirks Mode - documents with an older DOCTYPE (or without a DOCTYPE) are displayed using quirks mode. Quirks mode pages tend too look very different when displayed on different browsers.

Note: Data is anonymized and aggregated to show averages. No site specific data is ever shown.