Developing Mobile Applications with Force.com and Sencha Touch - Part 1, Build a Visualforce Custom Component to host our JavaScript application.

PocketCRM_APP1_1.component.js

<apex:component>
    <script type="text/javascript">
        //==============================================================================================
        //APPLICATION
        //The Application class is the entry point into your Sencha Touch application.
        //==============================================================================================
        Ext.application({
            name: "PocketCRM",
            //The application's startup routine once all components are loaded.
            launch: function () {

                //Instantiate your main list view for Leads.
                var mainView = Ext.create('Ext.Panel', {
                    fullscreen: true,
                    html: 'Welcome to PocketCRM!'
                });

                //Launch the primary fullscreen view and pass in the main view.
                Ext.Viewport.add([mainView]);
            }
        });
    </script>
</apex:component>