jQuery UI: How to use ui-widget-overlay by itself?

Question

I am trying to create an overlay, similar to the one that jQuery UI Dialog uses. I can create the overlay like this:

var $overlay = $('<div class="ui-widget-overlay"></div>').hide().appendTo('body');

//...later in my script
$overlay.fadeIn();

But the overlay cuts off when I scroll down. I noticed that jQuery UI is setting the width and height on that div dynamically. So I would like to reuse this functionality instead of reinventing the wheel. How can I create an overlay like this, or reuse the one in jQuery UI?

Solution:

Set the width/height of the overlay to be the width/height of the document, then bind a function on the window resize event to adjust the overlay width/height to match the new document width/height:

$(document).ready(function(){
    var $overlay = $('<div class="ui-widget-overlay"></div>').hide().appendTo('body');

    $('.trigger').click(function(){
        $('div').slideDown();
        $('.ui-widget-overlay').fadeIn();
        setOverlayDimensionsToCurrentDocumentDimensions(); //remember to call this when the document dimensions change
    });

    $(window).resize(function(){
        setOverlayDimensionsToCurrentDocumentDimensions();
    });
});

function setOverlayDimensionsToCurrentDocumentDimensions() {
    $('.ui-widget-overlay').width($(document).width());
    $('.ui-widget-overlay').height($(document).height());
}

Note that whenever the height of the document changes (adding elements, animating elements that slide down, etc), you will need to resize the overlay.

Answer 1

As of jQuery 1.4.4, it looks like it's as easy as:

$.ui.dialog.overlay.create();

Update

Here is a fiddle.

The code above returns the HTML element, so it should be use like this:

$("body").append($.ui.dialog.overlay.create());

Update 2

As was said, this doesn't work in jquery 1.10. To fix this, I created my own overlay:

<div id="loading" style="display: none;">   
    <div class="loading-container">         
        <img src="/img/loading.gif"/>
    </div>                                  
</div>                                      

(the image is just a random image I wanted to display in the middle to indicate that the page was loading) Then I added this CSS:

/* loading overlays */       
#loading {                   
    position: fixed;         
    top: 0;                  
    left: 0;                 
    width: 100%;             
    height: 100%;            
    background-color: #000;  
    filter:alpha(opacity=50);
    -moz-opacity:0.5;        
    -khtml-opacity: 0.5;     
    opacity: 0.5;            
    z-index: 10000;          
}                            
.loading-container {         
    position:fixed;          
    top: 50%;                
    left: 50%;               
}                            

Then one can call $('#loading').show() and $('#loading').hide() to hide and remove it.

I had to tweak the answer here: stack overflow response