Saturday, June 19, 2010

IE7 is why I drink so much

Cool bug in IE7; I think I ran across it years ago in IE6, but back then I thought everything any browser did was essentially magic so I didn't worry too much. Make a table. Put rows in your table, rows filled with glorious content. Give some columns — header and data cells alike — a class, like maybe "hideMe". Put a control somewhere on your page, preferably a checkbox. Wire that up to a Javascript handler that adds/removes a class from the enclosing table. Maybe your class can be called "hide". It is not important what these things are called. Please don't lose sight of the forest by becoming preoccupied with the color of the lichen on the trees. Now. Add some CSS such that a table cell (or header cell) with class "hideMe" inside a table with class "hide" is not displayed.

   table.hide th.hideMe, table.hide td.hideMe {
     display: none;
OK now what have we got? We've got a table with some columns and a control that you can click to make some columns go away. It's like a "peek a boo" game. Sometimes dogs really freak out over stuff like this. Now, let's say you want to use something like this for real. Let's say you want a table for something actually useful, and you want a "condensed" mode and a "full" mode. Thus your "condensed" mode will involve the outer table tag having that "hide" class, while the "full" mode will not. Possibly you'd like your page to start off in condensed mode, because the "full" mode has columns that only dumb people want to look at. This brings us to IE7. Your page loads, and you set things up so that the table has the "hide" class, and sure enough the "hideMe" columns are not shown. Great! That's exactly what we wanted! However we have to put that checkbox on there so that the dumb people can toggle the display of "hideMe" columns. So we do. In browsers developed outside of Mordor, everything works exactly like you'd expect. Not in IE7. IE7, perhaps like its Balrog predecessor IE6, has something up it's sleeve. When the page first loads, the hidden columns are hidden. Click that checkbox. Do you see the columns? No? Well, that's because IE7 has decided that table sub-elements hidden when the table is first rendered will never ever be visible ever, even if Elrond and Gandalf throw Frodo into the volcano and jump in after him. Note that if you load your page configured for dumb people, with the "hideMe" columns visible, then everything works. Things are just problematic when parts of tables (and just tables) are hidden upon initial DOM rendering. (Yes, this applies to stuff dynamically added to the DOM later — the Dark Lord is pretty thorough.) I don't know of any good way around this. A bad way around it is to make sure that things are set up in "everything visible" mode upon initial DOM rendering, and then have something come back in a few milliseconds and make things look the way you actually want them to look. I suspect that IE7 users have so many bruises on their brains that the page wiggle thusly induced might actually seem comforting and familiar, like the smell of burned waffles at your grandparents' house.

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