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What is the difference between null and undefined in JavaScript?
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alert(typeof TestVar); //shows undefined
null is an assignment value. It can be assigned to a variable as a representation of no value:
var TestVar = null;
alert(TestVar); //shows null
alert(typeof TestVar); //shows object
From the preceding examples, it is clear that undefined and null are ...
Private vs Public in Cache-Control
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The only difference is that with Private you are not allowing proxies to cache the data that travels through them. In the end, it all boils down to the data contained in the pages/files you are sending.
For example, your ISP could have an invisible prox...
Ineligible Devices section appeared in Xcode 6.x.x
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With the release of Xcode 6.3.1, check first the Update 5
Verify that "iOS Deployment Target" is <= the version of your iDevice.
You find this option in "Build Settings" tab when you click on a target of your projec...
What is a mixin, and why are they useful?
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A mixin is a special kind of multiple inheritance. There are two main situations where mixins are used:
You want to provide a lot of optional features for a class.
You want to use one particular feature in a lot of different classes.
For an example of number one,...
SQLAlchemy: cascade delete
I must be missing something trivial with SQLAlchemy's cascade options because I cannot get a simple cascade delete to operate correctly -- if a parent element is a deleted, the children persist, with null foreign keys.
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How to make a SPA SEO crawlable?
...wlable by google based on google's instructions . Even though there are quite a few general explanations I couldn't find anywhere a more thorough step-by-step tutorial with actual examples. After having finished this I would like to share my solution so that others may also make use of it and poss...
How to find out client ID of component for ajax update/render? Cannot find component with expression
...to a <p:tab> of a <p:tabView> residing in a <p:layoutUnit> of a <p:layout> . Here is the inner part of the code (starting from p:tab component); the outer part is trivial.
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How to prevent robots from automatically filling up a form?
I'm trying to come up with a good enough anti-spamming mechanism to prevent automatically generated input. I've read that techniques like captcha, 1+1=? stuff work well, but they also present an extra step impeding the free quick use of the application (I'm not looking for anything like that please)...
How do you run JavaScript script through the Terminal?
...to run a C program make filename then ./ filename . How do you do this with .js files?
15 Answers
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SHA1 vs md5 vs SHA256: which to use for a PHP login?
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Neither. You should use bcrypt. The hashes you mention are all optimized to be quick and easy on hardware, and so cracking them share the same qualities. If you have no other choice, at least be sure to use a long salt and re-h...