In this topic, we will present some tools that can help developers a lot while implementing Ext JS applications. You can find all the links of the tools mentioned here at the end of this topic.

The first tool is JSLint. JSLint is a tool that can help you to find JavaScript errors and can also help you to clean your code.

The second tool is YSlow. YSlow analyzes web pages and tells you why they're slow based on the rules for high performance websites. YSlow is a Firefox add-on integrated with the popular Firebug web development tool.

Ext JS is a JavaScript framework, and JavaScript performance is a topic that is a concern for a lot of companies. The minimum the user needs to load on the browser, the better. That is why it is very important to make a production build using Sencha Cmd and not simply deploy all the application files on production.

Sencha Cmd is also going to minify the Ext JS CSS file to a smaller CSS, and we can also include only the CSS for the components that we...