The difference is that some browsers allow you to overwrite the value of `undefined`. However, `void anything` always returns real *undefined*.

    undefined = 1;
    console.log(!!undefined); //true
    console.log(!!void 0); //false

`undefined` [has normal variable semantics that not even strict mode can fix](http://jsfiddle.net/9y2sr/) and requires run-time look-up. It can be shadowed
like any other variable, and the default global variable `undefined` is not read-only in ES3. 

`void 0` is effectively a compile time bulletproof constant for `undefined` with no look-up requirements. It is 
like writing `null` or `true`, instead of looking up a variable value. It works out of the box without any safety arguments and is shorter to write. It is better in every way.

Use `undefined`. Its more commonly known than `void(0)`.

Parentheses here are optional, `void 0`, `void(0)` and `void (0)` are equivalent. The `void` is a unary operator with a right-to-left associativity, hence the value is placed at the right of it: 

`void &lt;VALUE&gt;`.

For second question, you need to use `undefined` directly while avoiding unneeded operand evaluation to retrieve the same `undefined` value. 

More info in the reference: https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Operators/void

I&#39;ve never used Git before and would like to learn.

I have a private repository with GitHub.

I&#39;ve installed the EGit plugin for Eclipse.

I have a workspace where I do my work, generally: `~/Documents/workspace`.

I am able to add my GitHub repository and download it, but in doing so it creates `~/MyRepository`.

When I create a project, do I need to point it to `~/MyRepository`?

Also, how come when I make an edit and I say push to upstream it says up to date?

How do I set up Eclipse/EGit with GitHub?

In SOAP-UI I am making a request to a web service like this:

    &lt;soapenv:Envelope xmlns:soapenv=&quot;http://schemas.xmlsoap.org/soap/envelope/&quot; xmlns:xxx=&quot;http://xxx.call/&quot;&gt;
       &lt;soapenv:Header/&gt;
       &lt;soapenv:Body&gt;
          &lt;cotf:call_XXX&gt;
             &lt;!--Optional:--&gt;
             &lt;arg0&gt;
                &lt;!--Optional:--&gt;
                &lt;parameter1&gt;some text&lt;/parameter1&gt;
                &lt;!--Optional:--&gt;
                &lt;parameter2&gt;XML string&lt;/parameter1&gt;
             &lt;/arg0&gt;
          &lt;/cotf:call_XXX&gt;
       &lt;/soapenv:Body&gt;
    &lt;/soapenv:Envelope&gt;

What I would like to know is how I can pass an XML string on parameter 2 since if I put the XML string directly it assumes the XML string nodes as request parameters....

Thanks


SOAP-UI - How to pass xml inside parameter

What exactly is the difference between `undefined` and  `void 0` ?

Which is preferred and why?

JavaScript `undefined` vs `void 0`

<p>What exactly is the difference between <code>undefined</code> and  <code>void 0</code> ?</p>
<p>Which is preferred and why?</p>


Is there a way in JavaScript to check if a string is a URL?

RegExes are excluded because the URL is most likely written like `stackoverflow`; that is to say that it might not have a `.com`, `www` or `http`.

Check if a JavaScript string is a URL

What&#39;s the correct way to write a `for-in` loop in JavaScript? The browser doesn&#39;t issue a complaint about either of the two approaches I show here. First, there is this approach where the iteration variable `x` is explicitly declared:

    for (var x in set) {
        ...
    }

And alternatively this approach which reads more naturally but doesn&#39;t seem correct to me:

    for (x in set) {
        ...
    }


&quot;var&quot; or no &quot;var&quot; in JavaScript&#39;s &quot;for-in&quot; loop?

Hey everyone &amp;mdash; [HTML5 Boilerplate](http://html5boilerplate.com/) and [HTML5 Reset](http://html5reset.org/) are two HTML, CSS, and JavaScript templates with a lot of modern best practices built-in. Their goals are largely the same:

 * Fast, robust, modern Web development 
 * HTML5 (duh!)
 * Cross-browser normalization (including support for IE6 and mobile browsers)
 * Progressive enhancement and graceful degradation
 * Performance optimizations
 * Not a framework, but the starting point for your next project

Obviously, they&#39;re very similar in function. In what ways are their implementations different (for example, perhaps IE-specific CSS fixes are achieved using different techniques)? Are they at all different in scope? It seems like HTML5 Boilerplate is a bit larger (build tools, server configuration, etc.), but it&#39;s hard to know where it goes beyond HTML5 Reset when it comes to the actual site that people will see.

HTML5 Boilerplate vs. HTML5 Reset

I want to reload a page using JavaScript but I want to clear cache too, so on page refresh the page has latest versions of everything from server.  
Other browsers except IE are not getting latest content.

Any solution for IE9?

window.location.reload with clear cache

How should I parse JSON using Node.js? Is there some module which will validate and parse JSON securely?

How to parse JSON using Node.js?

I am really confused as to when JavaScript returns `null` or `undefined`. Also different browsers seem to be returning these differently.

Could you please give some examples of `null`/`undefined` with the browsers that return them.

While I am now clear on the `undefined` aspect, I am still not 100% clear on `null`. Is it similar to a blank value?

E.g. You have a text box which does not have any value set. Now when you try to access its value, will it be `null` or `undefined` and are they similar?

When is null or undefined used in JavaScript?

I&#39;ve been writing JavaScript for quite a long time now, and I have never had a reason to use `null`. It seems that `undefined` is always preferable and serves the same purpose programmatically. What are some practical reasons to use `null` instead of `undefined`?

What reason is there to use null instead of undefined in JavaScript?

Other than creating a function, is there a shorter way to check if a value is `undefined`,`null` or `false` only in JavaScript?


**The below if statement is equivalent to `if(val===null &amp;&amp; val===undefined val===false)`**
The code works fine, I&#39;m looking for a shorter equivalent.

    if(val==null || val===false){
      ;
    }
    
Above `val==null` evaluates to true both when `val=undefined` or `val=null`.

I was thinking maybe using bitwise operators, or some other trickery.

JavaScript check if value is only undefined, null or false

I&#39;m checking `if(response[0].title !== undefined)`, but I get the error:

&gt; Uncaught TypeError: Cannot read property &#39;title&#39; of undefined.


Test if something is not undefined in JavaScript

A new problem has arisen for me as I tried to run my script on a different PHP Server.

ON my old server the following code appears to work fine - even when no `s` parameter is declared.  

    &lt;?php
     if ($_GET[&#39;s&#39;] == &#39;jwshxnsyllabus&#39;)
    echo &quot;&lt;body onload=\&quot;loadSyllabi(&#39;syllabus&#39;, &#39;../syllabi/jwshxnporsyllabus.xml&#39;,         &#39;../bibliographies/jwshxnbibliography_&#39;)\&quot;&gt;&quot;;
    if ($_GET[&#39;s&#39;] == &#39;aquinas&#39;)
    echo &quot;&lt;body onload=\&quot;loadSyllabi(&#39;syllabus&#39;, &#39;../syllabi/AquinasSyllabus.xml&#39;)\&quot;&gt;&quot;; 
     if ($_GET[&#39;s&#39;] == &#39;POP2&#39;)
    echo &quot;&lt;body onload=\&quot;loadSyllabi(&#39;POP2&#39;)\&quot;&gt;&quot;;
    elseif ($_GET[&#39;s&#39;] == null)
    echo &quot;&lt;body&gt;&quot;
    ?&gt;

But now, on a my local server on my local machine (XAMPP - Apache) I get the following error when no value for `s` is defined.

    Notice: Undefined index: s in C:\xampp\htdocs\teaching\index.php on line 43
    Notice: Undefined index: s in C:\xampp\htdocs\teaching\index.php on line 45
    Notice: Undefined index: s in C:\xampp\htdocs\teaching\index.php on line 47
    Notice: Undefined index: s in C:\xampp\htdocs\teaching\index.php on line 49

What I want to happen for the script to call certain javascript functions if a value is declared for `s`, but if nothing is declared i would like the page to load normally. 

Can you help me?


php $_GET and undefined index

    void run() {
        ...
        if (done) return cancel();
        ...
    }

where `cancel()` return `void`. This won&#39;t compile... and I can *almost* understand why. But if I want to return a void from a void, why not? Instead, I end up writing something like this:

    if (done) {
        cancel();
        return;
    }

I&#39;m not looking for code style suggestions, I want to know why Java expressly prohibits this type of void return. Any info is appreciated, thanks.

Why can&#39;t I explicitly return void from a method?

Which is more correct way to return from function:

    void function() {
      // blah some code
    }

OR

    void function() {
      // blah some code
      return;
    }

___
Rationale for second way:

1. It expresses developer intentions more clearly.
2. It helps detecting function end at pre-compile time:

Suppose you have such scenario- you have bunch of functions and you must inject some code at the end of those functions. But for some reasons you don&#39;t want / or can&#39;t modify such huge amount of functions. What can you do about that ? `Return` &amp; `macro` comes into play, for example:

    #include&lt;stdio.h&gt;
    
    #define MAX_LINES 1000
    #define XCAT(a,b) a##b
    #define CAT(a,b) XCAT(a,b)
    #define return returns[__LINE__] = 1;\
            if (returns[__LINE__])\
               {printf(&quot;End of function on %d line.\n&quot;,__LINE__);}\
            int CAT(tmp,__LINE__); \
            if ((CAT(tmp,__LINE__)=returns[__LINE__], returns[__LINE__] = 0, CAT(tmp,__LINE__)))\
                  return
     
    static int returns[MAX_LINES];

    
    void function1(void) {
        return;
    }
    
    void function2(void) {
        return;
    }
    
    int main()
    {
        function1();
        function2();
    
        return 0;
    }




Returning from a void function

I am not sure what the difference is between specifying Unit as the return type of my scala method or leaving out the return type altogether. What is the difference?

Can anyone please advise?

Should I use Unit or leave out the return type for my scala method?

I have a few static util methods in my project, some of them just pass or throw an exception. There are a lot of examples out there on how to mock a static method that has a return type other than void. But how can I mock a static method that returns void to just &quot;`doNothing()`&quot;?

The non-void version uses these lines of codes:

    @PrepareForTest(StaticResource.class)
...

    PowerMockito.mockStatic(StaticResource.class);

...

    Mockito.when(StaticResource.getResource(&quot;string&quot;)).thenReturn(&quot;string&quot;);


However if applied to a `StaticResources` that returns `void`, the compile will complain that `when(T)` is not applicable for void... 

Any ideas?

A workaround would probably be to just have all static methods return some `Boolean` for success but I dislike workarounds.

How do I mock a static method that returns void with PowerMock?

In API

&gt; &quot;The Void class is an uninstantiable placeholder class to hold a
&gt; reference to the Class object representing the Java keyword void.&quot;


1. What is &quot;uninstantiable&quot; place holder class? When will `java.lang.Void` be used? If the class  is &quot;uninstantiable&quot;, what use is it?
2. What is difference between `java.lang.Void` and `void`?

Content Type	Original Author	Original Content on Stackoverflow
Question	Pacerier	View Question on Stackoverflow
Solution 1 - Javascript	duri	View Answer on Stackoverflow
Solution 2 - Javascript	Esailija	View Answer on Stackoverflow
Solution 3 - Javascript	Daniel A. White	View Answer on Stackoverflow
Solution 4 - Javascript	user422039	View Answer on Stackoverflow

JavaScript `undefined` vs `void 0`

Javascript Problem Overview

Javascript Solutions

Solution 1 - Javascript

Solution 2 - Javascript

Solution 3 - Javascript

Solution 4 - Javascript

SOAP-UI - How to pass xml inside parameter

How do I set up Eclipse/EGit with GitHub?

Attributions