Ext JS Screencast #002 Ext.extend

Here we discuss the Ext.extend method and demonstrate how you can use it to your advantage.

Category:

Science & Technology

Tags:

• Extjs
• ext
• js
• javascript
• java
• script
• web
• development
• webdevelopment
• 2.0
• web2.0
• web2
• firefox
• firebug
• howto
• how
• to

[beachhunt]

Thanks muchly, this was a helpful video. For some reason it all clicked into place.

[tdginnovations]

Thanks dude.

[khashayar581]

Hey dude! it's great. just keep going.

thanks.

[lylytyger]

Should be noted that here Jay presents 'the old way' Ext.extend method, commonly used in Ext 1.x; starting with Ext 2.x there is also a new approach of using Ext.extend without the need to explicitly define the SubClass constructor(e.g the var b = function (){}; part).

[lukemoynihan]

Thanks very much, I just went to extend my first Ext class and your tutorial helped a lot to understand what is required. :)

[Arythmael]

YouTube won't let me post the JavaScript.

[Arythmael]

YouTube won't let me post the JavaScript example. But just create a function, A. Add a method X to its prototype that alerts "Hi" to the user. Create a function B. Instantiate an instance of A as Test1. Use Ext to extend the A class with the superclass B (nothing new added). Now instantiate another instance of A as Test2.

Call the X method on Test1 (you see the alert).

Call the X method on Test2.

[Arythmael]

Yeah, but pretty worthless. The Ext.extend method claims to extend an existing CLASS, but ends up blowing away any prototype already defined for it. I have an example, but I'll have to paste this in separate comments because even though YouTube says I had 6 characters left, when I tried to post the whole comment it says I have too many characters (sigh).

[ucrstevetaebo]

Please keep this coming. I am a subscriber now. I learn so much than reading the online docs on extjs's website.