Recently I ran into an issue with several websites and their functionality, or lack thereof, on Mobile Safari in iOS 4.3.3 on the iPad.
Mobile Safari doesn’t give you much in the way of native debug tools. There is a debug console, which will display, at least in theory, any CSS, HTML or Javascript errors.
The only problem is that it won’t actually display all HTML errors. For instance the problem I ran into was an HTML tag mismatch between an opening H2 and a closing H3. Mobile Safari on iOS 5.1 displayed the page as designed, however on iOS 4.3.3 the bad closing tag was omitted which meant that all the children of that H2 had the CSS style “hidden” applied to them due to a class assignment.
You would think that this might trigger an error code in the debug console, however no such error occurred, and using the Safari iOS 4.3.3 – iPad user agent in desktop Safari on Mac OS X did not exhibit the error.
In searching for a tool to assist with debugging this problem natively on the iPad I ran across a great bookmarklet by Mark Perkins, called Snoopy.
This bookmarklet gives you all kinds of nifty information about the page you are looking at, including a view of the generated source. Thanks to this tool I was able to find out exactly what was breaking the display on the iPad.
One of the touted features of the unibody design MacBook Pro line was the introduction of two different graphics processing units [1]. Initially they shared two Nvidia GeForce chipsets. Beginning with the Core i5 and Core i7 models, this was changed to use an Intel HD Graphics chipset and either an Nvidia chipset or an AMD chipset (depending on the model and year of introduction).
This was put forth as a great power savings feature, but as many users have seen it has had unintended consequences. [2, 3, 4]
I have had no real issues involving this until I fired up Photoshop CS5 last night and found that the canvas window was missing! Now to be fair this doesn’t appear to be a problem on Snow Leopard, but nonetheless it was passing strange. After some diligent searching, I discovered that the solution appears to be turning off the automatic graphics switching and rebooting the laptop. (Hint: it’s in the Energy Saver system preference pane)
After doing this all was once again well with Photoshop. So if you encounter some odd graphics issues with your unibody MacBook Pro and Lion, try it and see if it helps.