When set page zoom/scale factor to a value < 1, then the JS code `element.content.scrollTop++` will be affected by this And the page auto scroll will not work. This problem exists in both newest Chrome 27 and Firefox 22. Reason for this: (1)In fact, zoom/scale operator should NOT apply to the point/position type, but only to the length type; (2)Or maybe we can change the internal DOM layput impl's type from int to double? (3)I had to say, the testcase expects a "continuous" style changing behavor, while discretized int-type values should always give a gap; void Element::setScrollTop(int newTop) { document()->updateLayoutIgnorePendingStylesheets(); if (RenderBox* rend = renderBox()) rend->setScrollTop(static_cast<int>(newTop * rend->style()->effectiveZoom())); //<--- }
Created attachment 206298 [details] Testcase for this bug report Load this page, and change the page zoom to <1 value, then the auto scroll will stop working