<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>CSS Test: Absolutely positioned inline-block element with percentage based height set to 'auto' and over-constrained values</title> <link rel="author" title="Microsoft" href="http://www.microsoft.com/" /> <link rel="reviewer" title="GĂ©rard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/" /> <!-- 2012-09-05 --> <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#abs-replaced-height" /> <link rel="match" href="absolute-replaced-height-012-ref.xht" /> <meta name="assert" content="An absolutely positioned inline-block replaced element with percentage height resolves based on the containing block height when such height can be resolved." /> <style type="text/css"> #div1 { position: relative; height: 2in; } div div { border: solid green; height: 1in; position: absolute; top: 1in; width: 300px; } iframe { border: solid red; bottom: 1in; margin-bottom: 0.5in; margin-top: 0.5in; position: absolute; top: 0.5in; width: auto; } /* 0.5in : 'top' + 0.5in : 'margin-top' + 3px : 'border-top-width' medium which is often resolved as 3px + 0 : 'padding-top' + 1in : 'height' 50% of height of containing block + 0 : 'padding-bottom' + 3px : 'border-bottom-width' medium which is often resolved as 3px + 0.5in : 'margin-bottom' + 1in : 'bottom' ================ 342px : height of containing block (192px) So, bottom has to be ignored and forced to have the value that will balance the equation. So, this brings up 0.5in : 'top' + 0.5in : 'margin-top' + 3px : 'border-top-width' medium which is often resolved as 3px + 0 : 'padding-top' + 1in : 'height' 50% of height of containing block + 0 : 'padding-bottom' + 3px : 'border-bottom-width' medium which is often resolved as 3px + 0.5in : 'margin-bottom' + (solve) : 'bottom' ================ -246px : height of containing block (192px) So, the solved bottom value should be -54px . */ </style> </head> <body> <p>Test passes if there is <strong>no red</strong>.</p> <div id="div1"> <iframe height="50%"></iframe> <div></div> </div> </body> </html>