Look at this example:http://jsfiddle.net/nvcode/BnGyu/2/Now it is clearly obvious that the browser can work out the width correctly as the first div is fully filled but on the second div I place a width of 98% and 1% padding either side, making a total of 100%.The browser knows that 100% is full width of the parent, so why is the child div not fill the space of the parent?Even if you change the value of the widths it breaks even more?