I thing you are using node-webkit,So its run on single thread,it's possible i can use npm and other client side framework(AngularJS,etc) and socket.io
The XDK does use node-webkit as a key building block for the application, but it does not expose nodejs for use outside the XDK. You can install and use your own instance of nodejs separately if there are tools you would like to use to enhance the development process. Your HTML5 app project files are stored on your local filesystem, so it is possible to use your own nodejs instance and tools with your project, independently of the XDK.
Also, we are making improvements in the XDK so that changes to files made outside the XDK, while the XDK is running, are more easily captured by the XDK components.
Thanks Paul,And one more thing if its possible to use WebGL(Three,js) in xdk for IOS
WebGL is only supported in the Crosswalk for Android container. It is not supported in the native webview on Android and iOS, I'm not sure about Windows Phone 8. Note that the XDK does not dictate what features exist or do not exist on a platform (I know, this is confusing). The XDK creates a "bundle" that is wrapped up in native code and which then initializes a "native webview" on the device which then interprets or runs your HTML5 code. That "native webview" can be thought of as an embedded browser built into the device. So the XDK is taking advantage of that built in embedded browser to create an app. This is exactly how PhoneGap also works.
See this page http://caniuse.com/webgl for some info regarding where webGL is supported.
The reason it works in the Crosswalk build is because we replace the native webview with a custom webview. However, we can only do that on Android 4.x. It is not possible to do that on iOS or Win8 and most other mobile platforms.
p.s. To understand which columns in a caniuse.com table are relevant to the native webview, see this image: