<!DOCTYPE html> <html class="reftest-wait"> <head> <title>displaystyle</title> <meta charset="utf-8"/> <script type="text/javascript"> function doTest() { document.getElementById('mathOperator'). setAttribute('mathbackground', 'red'); document.documentElement.removeAttribute("class"); } window.addEventListener("MozReftestInvalidate", doTest, false); </script> </head> <body> <!-- Test dynamic change (see bug 832800) --> <math> <mstyle displaystyle="true"> <mfrac> <mrow> <mi>X</mi> <mo id="mathOperator">+</mo> <mfrac> <mrow><mi>X</mi></mrow> <mrow><mi>X</mi></mrow> </mfrac> </mrow> <mrow> <mi>X</mi> </mrow> </mfrac> </mstyle> </math> </body> </html>