jQuery Mobile development can be done in your browser with your browser's debugger.
Sencha began by building frameworks for full-featured apps that live in your browser, then extended its expertise to produce Sencha Touch for tablets and smartphones. Sencha's Ext JS is the foundation of a line of products that includes compilers and IDEs. Sencha Touch is part of this product line.
Sencha Touch, the core used to create mobile apps, is free for both open source and proprietary development as long as your code won't run as an embedded part of a product that ships more than 5,000 units. This is Sencha's free carrot to get people interested in its tool. The company also sells support and courses to anyone who needs a bit of help.
Sencha Touch is an increasingly small part of a bigger landscape. Sencha sells a Sencha Touch Bundle that includes a number of extras such as Architect, a visual editor for creating apps, and Charts, a collection of charting routines that makes everything looker nicer. The Bundle is $695 for one developer, and there are volume price breaks for five and 20 developers. A more expensive Sencha Complete bundle tosses in the licenses to tackle desktop jobs.
The Sencha Touch documentation includes embedded live examples that you can execute while reading.
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