From Learn About the Ext JavaScript Library

"The GuiDesiger widget is a panel, where the user designs a GUI. The result can be saved in a JSON file and then be used in an autoload."

I'm new to ExtJS. Can you please explain how to "autoload"?

See the forum thread for more examples but in general this is how to use it.

new Ext.Viewport({ layout: 'fit', items : new Ext.ux.JsonPanel({autoLoad:'json/designer.json'}) }).show();