Take a look at [Simple JavaScript Inheritance][1] and [Inheritance Patterns in JavaScript][2].

The simplest method is probably functional inheritance but there are pros and cons.


  [1]: http://ejohn.org/blog/simple-javascript-inheritance/
  [2]: http://www.bolinfest.com/javascript/inheritance.php

Douglas Crockford has some very good explanations of inheritance in JavaScript:

1. [prototypal inheritance][1]: the &#39;natural&#39; way to do things in JavaScript
2. [classical inheritance][2]: closer to what you find in most OO languages, but kind of runs against the grain of JavaScript


  [1]: https://crockford.com/javascript/prototypal.html
  [2]: https://crockford.com/javascript/inheritance.html

       extend = function(destination, source) {   
              for (var property in source) {
                destination[property] = source[property];
              }
              return destination;
        };

[Extending JavaScript][1]

You could also add filters into the for loop.


  [1]: http://www.htmlgoodies.com/html5/javascript/extending-javascript-objects-in-the-classical-inheritance-style.html#fbid=gxdrr8MOJm2

The normal behavior when using [`fadeIn`](http://api.jquery.com/fadeIn) and [`fadeOut`](http://api.jquery.com/fadeOut) is to use [the `display` property](https://developer.mozilla.org/en/CSS/display). However, this changes the layout of the page.

How can I make `fadeIn` and `fadeOut` not modify the layout of the page?

Fading elements in and out without changing the layout of the page

I would like to eliminate the HttpSession completely - can I do this in web.xml? I&#39;m sure there are container specific ways to do it (which is what crowds the search results when I do a Google search).

P.S. Is this a bad idea? I prefer to completely disable things until I actually need them.

Can I turn off the HttpSession in web.xml?

What is the right/best way to extend a javascript class so Class B inherits everything from the class A (class B extends A)?

Javascript extends class

<p>What is the right/best way to extend a javascript class so Class B inherits everything from the class A (class B extends A)?</p>


I want to use an if-statement to run code only if the user types in a letter or a number.

I could use 

```javascript
if (event.keyCode == 48 || event.keyCode == 49 || event.keyCode == 50 || ...) {
  // run code
}
```

Is there an easier way to do this? Maybe some keycodes don&#39;t work in all web browsers?

Detect numbers or letters with jQuery/JavaScript?

I am using a JS object to create graphs with Google visualization. I am trying to design the data source. At first, I created a JS object client-side.  

```
var JSONObject = {
  cols: [{
      id: &#39;date&#39;,
      label: &#39;Date&#39;,
      type: &#39;date&#39;
    },
    {
      id: &#39;soldpencils&#39;,
      label: &#39;Sold Pencils&#39;,
      type: &#39;number&#39;
    },
    {
      id: &#39;soldpens&#39;,
      label: &#39;Sold Pens&#39;,
      type: &#39;number&#39;
    }
  ],
  rows: [{
      c: [{
        v: new Date(2008, 1, 1),
        f: &#39;2/1/2008&#39;
      }, {
        v: 30000
      }, {
        v: 40645
      }]
    },
    {
      c: [{
        v: new Date(2008, 1, 2),
        f: &#39;2/2/2008&#39;
      }, {
        v: 14045
      }, {
        v: 20374
      }]
    },
    {
      c: [{
        v: new Date(2008, 1, 3),
        f: &#39;2/3/2008&#39;
      }, {
        v: 55022
      }, {
        v: 50766
      }]
    }
  ]
};

var data = new google.visualization.DataTable(JSONObject, 0.5);
```

Now I need to fetch the data dynamically. So I send an AJAX request to a page that returns the JSON string:
 
     &quot;cols: [{id: &#39;date&#39;, label: &#39;Date&#39;, type: &#39;date&#39;},
    {id: &#39;soldpencils&#39;, label: &#39;Sold Pencils&#39;, type: &#39;number&#39;},
    {id: &#39;soldpens&#39;, label: &#39;Sold Pens&#39;, type: &#39;number&#39;}],
      rows: [{c:[{v: new Date(2008,1,1),f:&#39;2/1/2008&#39;},{v: 30000}, {v: 40645}]},
          {c:[{v: new Date(2008,1,2),f:&#39;2/2/2008&#39;},{v: 14045}, {v: 20374}]},
    {c:[{v: new Date(2008,1,3),f:&#39;2/3/2008&#39;},{v: 55022}, {v: 50766}]}&quot;

This I save into a variable:

    var var1 = &quot;cols: [{i ....... 66}]}&quot;

and show as 

    alert(var1);

Now my task is to create a JS object from this string. This is not working. When I use a JS object, everything works fine and I am able to get my required graph. Now if I try putting the same value of string from the AJAX request which I confirmed from a alert message into a n object, the object is not getting created correctly. Please let me know your opinion and any correction or advices.


JSON string to JS object

I want to know how to list all methods available for an object like for example:

     alert(show_all_methods(Math));

This should print: 
    
    abs, acos, asin, atan, atan2, ceil, cos, exp, floor, log, max, min, pow, random,round, sin, sqrt, tan, …

How to display all methods of an object?

I&#39;m trying to debug a website, and I think that jQueryUI may not have loaded properly. How can I test if jQueryUI has loaded?

Testing if jQueryUI has loaded

When I set a pre element to contenteditable and put focus in it for editing, it receives a dotted border around it that doesn&#39;t look very nice. The border isn&#39;t there when focus is somewhere else.  
How do I remove that border?

Thanks

How do I remove the border around a focused contenteditable pre?

I am just trying to understand the `extends` keyword in Java Generics.

`List&lt;? extends Animal&gt;` means we can stuff any object in the `List` which **IS A** `Animal`

then won&#39;t the following also mean the same thing:

    List&lt;Animal&gt;

Can someone help me know the difference between the above two? To me `extends` just sound redundant here.

Thanks!

Generics : List&lt;? extends Animal&gt; is same as List&lt;Animal&gt;?

In Java, I can do the following: (assume `Subclass` extends `Base`):

    ArrayList&lt;? extends Base&gt; aList = new ArrayList&lt;Subclass&gt;();

What is the equivalent in C# .NET? There is no `? extends` keyword apparently and this does not work:

    List&lt;Base&gt; aList = new List&lt;Subclass&gt;();
 

C#&#39;s equivalent of Java&#39;s &lt;? extends Base&gt; in generics

I need to create a base class that extends `Activity` which does some common tasks in my application and extend my **activities** from it,in the following form:

***public BaseActivity extends Activity{....}***

***public SubActivity extends BaseActivity{...}***

in **SubActivity** I need to give values to some variables and UI components defined in **BaseActivity**, I may need to define a different layout for **SubActivity** according to some flag value,  also(in **SubActivity** ) I want to execute asyncTask that is defined in **BaseActivity**.

is this possible? if yes, is there any tutorial that may help?
thank you in advance


android how to create my own Activity and extend it?

In java when an interface extends another interface:

 1. Why does it implement its methods?
 2. How can it implement its methods when an interface can&#39;t contain a
    method body
 3. How can it implement the methods when it extends the other interface
    and not implement it?
 4. What is the purpose of an interface implementing another interface?

This has major concepts in Java!

**EDIT:**  

    public interface FiresDragEvents {
    
      void addDragHandler(DragHandler handler);
    
      void removeDragHandler(DragHandler handler);
    }


    public interface DragController extends FiresDragEvents {
    
      void addDragHandler(DragHandler handler);
    
      void removeDragHandler(DragHandler handler);
    
      void dragEnd();
    
      void dragMove();
    }

**In eclipse there is the implement sign besides the implemented methods in `DragController`.**
   
**And when I mouse-hover it, it says that it implements the method!!!**

Interface extends another interface but implements its methods

I am currently transforming from `Java` to `Javascript`, and it&#39;s a bit hard for me to figure out how to extend objects the way I want it to do.

I&#39;ve seen several people on the internet use a method called extend on object. The code will look like this:

    var Person = {
       name : &#39;Blank&#39;,
       age  : 22
    }
    
    var Robot = Person.extend({
       name : &#39;Robo&#39;,
       age  : 4
    )}

    var robot = new Robot();
    alert(robot.name); //Should return &#39;Robo&#39;
Does anyone know how to make this work?
I&#39;ve heard that you need to write 

    Object.prototype.extend = function(...);

But I don&#39;t know how to make this system work. If it is not possible, please show me another alternative that extends an object.

Content Type	Original Author	Original Content on Stackoverflow
Question	xpepermint	View Question on Stackoverflow
Solution 1 - Javascript	cletus	View Answer on Stackoverflow
Solution 2 - Javascript	Annabelle	View Answer on Stackoverflow
Solution 3 - Javascript	user922475	View Answer on Stackoverflow

Javascript extends class

Javascript Problem Overview

Javascript Solutions

Solution 1 - Javascript

Solution 2 - Javascript

Solution 3 - Javascript

Can I turn off the HttpSession in web.xml?

Fading elements in and out without changing the layout of the page

Attributions