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How to check a not-defined variable in JavaScript
...nly be done with try/catch, since typeof will treat an undeclared variable and a variable declared with the value of undefined as equivalent.
But, to check if a variable is declared and is not undefined:
if (yourvar !== undefined) // Any scope
Previously, it was necessary to use the typeof opera...
Tool to read and display Java .class versions
Do any of you know of a tool that will search for .class files and then display their compiled versions?
9 Answers
...
How do I set bold and italic on UILabel of iPhone/iPad?
How do I set bold and italic on UILabel of iPhone/iPad?
I searched the forum but nothing helped me. Could anyone help me?
...
Center content in responsive bootstrap navbar
...ng for. You need to remove the float: left from the inner nav to center it and make it a inline-block.
.navbar .navbar-nav {
display: inline-block;
float: none;
vertical-align: top;
}
.navbar .navbar-collapse {
text-align: center;
}
http://jsfiddle.net/bdd9U/2/
Edit: if you only want th...
Java 8 NullPointerException in Collectors.toMap
...ws a NullPointerException if one of the values is 'null'. I don't understand this behaviour, maps can contain null pointers as value without any problems. Is there a good reason why values cannot be null for Collectors.toMap ?
...
PHP 5.4 Call-time pass-by-reference - Easy fix available?
... I had this used in the old code for an object called event (&$event), and had to remove the ampersand for the error message to disappear.
– Natalia
Nov 16 '13 at 17:21
1
...
Is there a difference between authentication and authorization?
I see these two terms bandied about quite a bit (specifically in web-based scenarios but I suppose it's not limited to that) and I was wondering whether or not there was a difference.
...
How do I make a column unique and index it in a Ruby on Rails migration?
...1 for suggesting continuing to use the validates_uniqueness_of. The error handling is much cleaner using this method for the cost of a single indexed query I would suggest he does both
– Steve Weet
Sep 19 '09 at 22:08
...
define() vs. const
...d in const as well:
const BIT_5 = 1 << 5; // Valid since PHP 5.6 and invalid previously
define('BIT_5', 1 << 5); // Always valid
const takes a plain constant name, whereas define() accepts any expression as name. This allows to do things like this:
for ($i = 0; $i < 32; ++$i) {
...
What does new self(); mean in PHP?
...ends MyParentClass {
}
$a = MyChildClass::getInstance();
var_dump($a);
And you'd get this kind of output :
object(MyParentClass)#1 (0) { }
Which means self means MyParentClass -- i.e. here too, the class in which it is written.
With PHP < 5.3, that "the class in which it is written" ...