this are 200px

HTML example

should = 200px this green cell must be 400px wide
this blue cell should be exactly 600px wide

CSS example

should = 200px this green cell must be 400px wide
this blue cell should be exactly 600px wide

Source: http://www.gtalbot.org/BrowserBugsSection/MSIE8Bugs/table-width-colspan-test1.html