Maybe I should be waiting for another Wave.

The solution: hook onKeyUp and use setTimeout with a timeout of 0. Yugh. I hate DOM.

Big Fat Disclaimer: I actually tested this only on one browser.

for page in Page.objects.all():
  print page.title
  for comment in page.comments.all():
    print comment.

There will be a single query to fetch all pages, but there will be for every page another query to fetch its comments. Luckily, Django has got a nice trick up its sleave: select_related. Would I use instead of Page.objects.all(), Page.objects.select_related('comments').all() then Django will use a single joined query to prefetch comments for each page.

However, Django’s select_related only supports forward one-to-many references. No many-to-many; certainly no reverce many-to-many; no reverse one-to-many and no, not even reverse one-to-one (yet). A developer claims it’s impossible (which is bullshit), another asks for patches, which means he doesn’t care doing it himself.

It’s quite easy to manually code around the missing reverse select_related, but it takes too many ugly lines compared to the single word it could’ve been.

for(something) {
 str .= little_bit;
}

Why? Everytime a little bit is added to str, there must be a new string allocated big enough to contain str and the new little bit. Then the actual str must be copied in. In most languages there are constructs to efficiently build strings like this instead of concatenating. StringBuffer in C#. StringIO in Python.

But no, PHP has to be stupid. There is no nice construct and you’ll end up using concatenation. So, I thought to be smart and make use of PHP array’s and implode. Arrays are here for having elements added and removed all the time so they are properly buffered and should be great at having lots of small elements added. And when I want to pack it all into one big string, I can use PHP’s builtin implode function.

I wanted to try it out and created two scripts: a.php concats a little (10byte) string one million times and b.php appends it to an array and then implodes it. And because I’m also interested in the performance of implode I got a script c.php that’s identical to b.php but doesn’t implode afterwards. These are the results:

Indeed, string concatenation with all its allocation and copying is actually faster than plain simple array appending. PHP is stupid.

if (navigator.appName.match(/Internet Explorer/)) {
	fsel = document.createElement(\'<SELECT MULTIPLE>\');
} else {
	fsel = document.createElement(\'select\');
	fsel.multiple = true;
}