Try  

    $(&quot;some-selector&quot;).is(&#39;:hidden&#39;);
or   

    $(&quot;some-selector&quot;).is(&#39;:visible&#39;);  
  
Here are the docs for the &lt;a href=&quot;http://api.jquery.com/visible-selector/&quot;&gt;`:visible`&lt;/a&gt; and the &lt;a href=&quot;http://api.jquery.com/hidden-selector/&quot;&gt;`:hidden`&lt;/a&gt; selectors.

    $(&#39;.target&#39;).is(&#39;:hidden&#39;) // returns true if the element is hidden
    $(&#39;.target&#39;).is(&#39;:visible&#39;) // returns true if the element is visible



`UITextAlignmentCenter` seems to be deprecated in iOS 6. What are my alternatives?

What are good alternatives to UITextAlignmentCenter in iOS 6?

As in the title: does TypeScript support namespaces? If so, how do I use them?

Does TypeScript support namespace?

&gt; **Possible Duplicate:**  
&gt; [Testing if something is hidden with jQuery](https://stackoverflow.com/questions/178325/testing-if-something-is-hidden-with-jquery)  

&lt;!-- End of automatically inserted text --&gt;

In jQuery, suppose you have an element of some kind that you&#39;re hiding and showing, using `.hide()`, `.show()` or `.toggle()`. How do you test to see if that element is currently hidden or visible on the screen?

How do i test if something is hidden with jQuery?

> Possible Duplicate: 
> <a href="https://stackoverflow.com/questions/178325/testing-if-something-is-hidden-with-jquery" target="_blank" rel="noopener noreferrer">Testing if something is hidden with jQuery</a>

In jQuery, suppose you have an element of some kind that you're hiding and showing, using <code>.hide()</code>, <code>.show()</code> or <code>.toggle()</code>. How do you test to see if that element is currently hidden or visible on the screen?

I have a div and want to find the bottom position. I can find the top position of the Div like this, but how do I find the bottom position?

    var top = $(&#39;#bottom&#39;).position().top;
    return top;


Finding the position of bottom of a div with jquery

I bound an event on the change event of my select elements with this:

    $(&#39;select&#39;).on(&#39;change&#39;, &#39;&#39;, function (e) {

	});

How can I access the element which got selected when the change event occurs?

jQuery select change event get selected option

I&#39;m using this script to upload my image files: http://jsfiddle.net/eHmSr/

    $(&#39;.uploader input:file&#39;).on(&#39;change&#39;, function() {
      $this = $(this);
    
      $(&#39;.alert&#39;).remove();
            
      $.each($this[0].files, function(key, file) {
        $(&#39;.files&#39;).append(&#39;&lt;li&gt;&#39; + file.name + &#39;&lt;/li&gt;&#39;);
    
        data = new FormData();
        data.append(file.name, file);
    
        $.ajax({
          url: $(&#39;.uploader&#39;).attr(&#39;action&#39;),
          type: &#39;POST&#39;,
          dataType: &#39;json&#39;,
          data: data
        });
      });
    });

But when I click in upload button, the JavaScript console returns this error:

    Uncaught TypeError: Illegal invocation 

![jQuery Error][1]

Can you help me?


  [1]: http://i.stack.imgur.com/cxsX3.png

Jquery and HTML FormData returns &quot;Uncaught TypeError: Illegal invocation&quot;

I&#39;ve attempted to write a class in TypeScript that has a method defined which acts as an event handler callback to a jQuery event.


    class Editor {
        textarea: JQuery;

        constructor(public id: string) {
            this.textarea = $(id);
            this.textarea.focusin(onFocusIn);
        }

        onFocusIn(e: JQueryEventObject) {
            var height = this.textarea.css(&#39;height&#39;); // &lt;-- This is not good.
        }
    }

Within the onFocusIn event handler, TypeScript sees &#39;this&#39; as being the &#39;this&#39; of the class. However, jQuery overrides the this reference and sets it to the DOM object associated with the event. 

One alternative is to define a lambda within the constructor as the event handler, in which case TypeScript creates a sort of closure with a hidden _this alias.

    class Editor {
        textarea: JQuery;

        constructor(public id: string) {
            this.textarea = $(id);
            this.textarea.focusin((e) =&gt; {
                var height = this.textarea.css(&#39;height&#39;); // &lt;-- This is good.
            });
        }
    }

My question is, is there another way to access the this reference within the method-based event handler using TypeScript, to overcome this jQuery behavior?

Is there an alias for &#39;this&#39; in TypeScript?

I&#39;m simply trying to do something once the scroll position of the page reaches a certain height. However `scrollTop()` is returning 0 or `null` no matter how far down I scroll. This is the help function I&#39;m using to check the `scrollTop()` value: 

    $(&#39;body&#39;).click(function(){
        var scrollPost = $(document).scrollTop();
        alert(scrollPost);
    });

I&#39;ve tried attaching `scrollTop()` to `$(&#39;body&#39;)`, `$(&#39;html&#39;)` and of course `$(window)`, but nothing changes. 

Any ideas?

$(document).scrollTop() always returns 0

I developed cross platform software in c++. As I know, Linux .so exported all the symbols by default, well through `&quot;gcc -fvisibility=hidden&quot;` I can set all the exported symbols as hidden, then set `__attribute__(visibility(&quot;default&quot;))` for the class and function I want to export, so I can control what I want to export.

My question is, using CMake, how can I do the work as &quot;gcc -fvisibility=hidden&quot; control?

What is the CMake equivalent to &quot;gcc -fvisibility=hidden&quot; when controlling the exported symbol of a shared library?

I&#39;m developing an app for iOS and I&#39;m using the Storyboard with AutoLayout ON. One of my view controllers has a set of 4 buttons, and in certain circumstances i would like to make the first one disappear.

If I use the `setHidden:TRUE` method the UIButton become invisible but it still obviously take space in the view, and the result is an &quot;hole&quot; which I&#39;ve not been able to fill making the remaining UIButton to float towards the top of the main view.

In Android I would have simply used `View.GONE` instead of `View.INVISIBLE`, but in iOS I&#39;m stuck with this behaviour and I don&#39;t want to believe that the only solution is to manually (yes I mean programmatically) move the remaining elements to the top.

I thought I would have been able to do it setting some sort of Constraint to make everything as automatic as it is in Android but I&#39;ve had no luck. 

Before I turn Autolayout OFF, can someone point me to the right direction?

I&#39;m using the IB, but I&#39;m comfortable with programmatic stuff as well.

**UPDATE:**

Setting the component height to 0 doesn&#39;t help as well.

I tried something like this:

    UIButton *b;
    CGRect frameRect = b.frame;
    frameRect.size.height = 0;
    b.frame = frameRect;


iOS equivalent for Android View.GONE visibility mode

How can I hide a column in a WPF `DataGrid` through a Binding?

This is what I did:

    &lt;DataGridTextColumn Header=&quot;Column header&quot;
                        Binding=&quot;{Binding ColumnValue}&quot;
                        Width=&quot;100&quot;
                        ElementStyle=&quot;{StaticResource DataGridRightAlign}&quot;
                        Visibility=&quot;{Binding MyColumnVisibility}&quot; /&gt;

And this is what I got (besides the column still visible):

&gt; System.Windows.Data Error: 2 : Cannot find governing FrameworkElement or FrameworkContentElement for target element. BindingExpression:Path=MyColumnVisibility; DataItem=null; target element is &#39;DataGridTextColumn&#39; (HashCode=1460142); target property is &#39;Visibility&#39; (type &#39;Visibility&#39;)

How to fix the binding?

Binding Visibility for DataGridColumn in WPF

I was reading about the difference between two CSS properties `display:none` and `visibility:hidden` and encountered the **DOM reflow** term.

The statement was
&gt; `display: none` causes a DOM reflow whereas `visibility: hidden` does not. 

So my question is: 
### What is DOM reflow and how does it work?

What is DOM reflow?

I tend to have a lot of these in my code

    if(shouldElementBeVisible)
        $element.show()
    else
        $element.hide()

Is there any more elegant way packaged with javascript, jquery, or underscore? Ideally I want something that looks like this

    $element.showOrHideDependingOn(shouldElementBeVisible)

Content Type	Original Author	Original Content on Stackoverflow
Question	Favourite Onwuemene	View Question on Stackoverflow
Solution 1 - Jquery	gion_13	View Answer on Stackoverflow
Solution 2 - Jquery	Bruno Vieira	View Answer on Stackoverflow

How do i test if something is hidden with jQuery?

Jquery Problem Overview

Jquery Solutions

Solution 1 - Jquery

Solution 2 - Jquery

Does TypeScript support namespace?

What are good alternatives to UITextAlignmentCenter in iOS 6?

Attributions