Adding a loading mask to your ExtJS application

examplesextjscssloadingmaskui

Adding a loading mask like the one on the ExtJS API application is a nice way of showing the user that something is happening while their browser downloads the source code. It's also extremely easy to do.

First, place the following HTML above all of your javascript include tags, ideally just after the <body> tag:

<div id="loading-mask"></div>
<div id="loading">
  <div class="loading-indicator">
    Loading...
  </div>
</div>
<div id="loading-mask"></div>
<div id="loading">
  <div class="loading-indicator">
    Loading...
  </div>
</div>

If you are currently including javascript files inside the <head>, don't - put them at the bottom.

With a bit of CSS (see below), this provides a white mask over all underlying content, and a loading message. When everything has loaded, remove the mask like this:


Ext.onReady(function() {
  setTimeout(function(){
    Ext.get('loading').remove();
    Ext.get('loading-mask').fadeOut({remove:true});
  }, 250);
});

Ext.onReady(function() {
  setTimeout(function(){
    Ext.get('loading').remove();
    Ext.get('loading-mask').fadeOut({remove:true});
  }, 250);
});

The above simply fades out the HTML elements to reveal the now ready page. The setTimeout call gives your app a little time to render, which is useful if you're doing something like pulling external content down from the server.

Finally, here's the CSS I use to style up the loading mask. You'll need to download a loading image and stick it in the appropriate directory.

#loading-mask {
  position: absolute;
  left:     0;
  top:      0;
  width:    100%;
  height:   100%;
  z-index:  20000;
  background-color: white;
}

#loading {
  position: absolute;
  left:     50%;
  top:      50%;
  padding:  2px;
  z-index:  20001;
  height:   auto;
  margin:   -35px 0 0 -30px;
}

#loading .loading-indicator {
  background: url(../images/loading.gif) no-repeat;
  color:      #555;
  font:       bold 13px tahoma,arial,helvetica;
  padding:    8px 42px;
  margin:     0;
  text-align: center;
  height:     auto;
}
#loading-mask {
  position: absolute;
  left:     0;
  top:      0;
  width:    100%;
  height:   100%;
  z-index:  20000;
  background-color: white;
}

#loading {
  position: absolute;
  left:     50%;
  top:      50%;
  padding:  2px;
  z-index:  20001;
  height:   auto;
  margin:   -35px 0 0 -30px;
}

#loading .loading-indicator {
  background: url(../images/loading.gif) no-repeat;
  color:      #555;
  font:       bold 13px tahoma,arial,helvetica;
  padding:    8px 42px;
  margin:     0;
  text-align: center;
  height:     auto;
}

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I've built things on the web for 20 years, and used JavaScript before it was cool.

I've been working for myself since early 2023, going wherever my heart takes me - mostly playing with AI and UI.

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  • Engineering at Origin
  • Engineering management at PANW
  • UI engineering at PANW
  • UI engineering at C3 AI
  • Framework architecture at Sencha

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