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Elements order in a “for (… in …)” loop
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Quoting John Resig:
Currently all major browsers loop over the properties of an object in the order in
which they were defined. Chrome does this as well, except for a couple cases. [...]
This behavior is explicitly left undefined by the ECMAScript specifi...
Does JavaScript have a built in stringbuilder class?
... strings with the + or += operator are extremely slow on IE. This is especially true for IE6. On modern browsers += is usually just as fast as array joins.
When I have to do lots of string concatenations I usually fill an array and don't use a string builder class:
var html = [];
html.push(
"&l...
CSS: How to position two elements on top of each other, without specifying a height?
...exactly on top of each other. However, when I do that, the formatting gets all screwed up because the containing DIV acts like there is no height. I think this is the expected behavior with position:absolute but I need to find a way to position these two elements on top of each other and have the ...
Why does Apple recommend to use dispatch_once for implementing the singleton pattern under ARC?
...
dispatch_once() is absolutely synchronous. Not all GCD methods do things asynchronously (case in point, dispatch_sync() is synchronous). The use of dispatch_once() replaces the following idiom:
+ (MyClass *)sharedInstance {
static MyClass *sharedInstance;
@synchr...
Quicksort vs heapsort
... The most direct competitor of
quicksort is heapsort. Heapsort is
typically somewhat slower than
quicksort, but the worst-case running
time is always Θ(nlogn). Quicksort is
usually faster, though there remains
the chance of worst case performance
except in the introsort variant, which...
Jquery - How to make $.post() use contentType=application/json?
... to
1.Modify the source to make $.post always use JSON data type as it really is just a shortcut for a pre configured $.ajax call
Or
2.Define your own utility function that is a shortcut for the $.ajax configuration you want to use
Or
3.You could overwrite the $.post function with your own i...
In Node.js, how do I “include” functions from my other files?
Let's say I have a file called app.js. Pretty simple:
26 Answers
26
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Distributed sequence number generation?
I've generally implemented sequence number generation using database sequences in the past.
13 Answers
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What is InnoDB and MyISAM in MySQL?
...MyISAM
InnoDB is a storage engine for MySQL,
included as standard in all current
binaries distributed by MySQL AB. Its
main enhancement over other storage
engines available for use with MySQL
is ACID-compliant transaction support
MyISAM is the default storage engine
for the MySQ...
SQL Joins Vs SQL Subqueries (Performance)?
...explicit JOIN. In my experience IN is a very slow operator, since SQL normally evaluates it as a series of WHERE clauses separated by "OR" (WHERE x=Y OR x=Z OR...).
As with ALL THINGS SQL though, your mileage may vary. The speed will depend a lot on indexes (do you have indexes on both ID column...