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Why is isNaN(null) == false in JS?
...ull. The function isNaN() can be used to answer this question, but semantically it's referring specifically to the value NaN. From Wikipedia for NaN:
NaN (Not a Number) is a value of the numeric data type representing an undefined or unrepresentable value, especially in floating-point calculat...
Is “else if” faster than “switch() case”? [duplicate]
...r a more general case where you are writing a function that is going to be called >100k times. I tend to call these "multipliers". For example, an if-statement in a for loop in a recursive function has 2 multipliers from both the loop and function. A small improvement to the body of the if-statem...
How to set current working directory to the directory of the script in bash?
...
If you called the script as ./script, . is the correct directory, and changing to . it will also end up in the very directory where script is located, i.e. in the current working directory.
– ndim
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How to find the JVM version from a program?
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That JMX call returns the equivalent of "java.vm.version", not "java.version". These are usually (but not necessarily) the same.
– Alex Miller
Jun 21 '13 at 15:54
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jQuery Datepicker onchange event issue
I have a JS code in which when you change a field it calls a search routine. The problem is that I can't find any jQuery events that will fire when the Datepicker updates the input field.
...
Django: accessing session variables from within a template?
...ritten. Please note however, that although the view code above is still valid, nowadays there is a much simpler way of doing this. render() is a function very similar to render_to_response(), but it uses RequestContext automatically, without a need to pass it explicitly:
from django.shortcuts impor...
How can I print the contents of a hash in Perl?
...n C and C++. The reason it matters in this context is that in Perl, if you call a function with a hash value as the argument, that hash value gets listified and expanded into multiple arguments - so %hsh=("a" => 1, "b" => 2); foo(%hsh); would be equivalent to foo("a", 1, "b", 2). If you instea...
What's the purpose of SQL keyword “AS”?
...Joe Celko's SQL Programming Style':
A correlation name is more often
called an alias, but I will be formal.
In SQL-92, they can have an optional
AS operator, and it should be used
to make it clear that something is
being given a new name. [p16]
This way, if your team doesn't like the...
How to send a custom http status message in node / express?
...ke other middleware, except with
four arguments instead of three, specifically with the signature (err,
req, res, next). ... You define error-handling middleware last, after
other app.use() and routes calls
app.use(function(err, req, res, next) {
if (err instanceof JSONError) {
res...
Javascript foreach loop on associative array object
...tion(key, index) {
console.log(this[key]);
}, arr_jq_TabContents);
The callback function passed to .forEach() is called with each key and the key's index in the array returned by Object.keys(). It's also passed the array through which the function is iterating, but that array is not really usefu...