File upload widget for ExtJS 4.x

In a project I'm working on, I needed a flexible file upload panel with multiple file upload support. Unfortunately, the ExtJS built-in mechanisms (Ext.form.field.File) does not support multiple upload and there are some other limitations as well. I searched for a user contributed plugin, but I couldn't find a suitable one. Most of the contributions were written for older versions of ExtJS - 3.x or even 2.x. So I decided to write one myself, trying to use some advanced features of HTML5.

You may first check the live demo.

Using the window.onerror handler for logging javascript errors

I'm running a really large administration application with javascript based user interface. It is used by a large number of users on different computers with different operation systems and different browsers. Sometimes weird javascript errors occur. And when such error occurs, the browser stops the execution of the script and the users usually reports something like "it didn't work".

Luckily, there is a way how to handle this and although it may not cover 100% of all the errors, it might be helpful when dealing with errors at the client side. If you define the window.onerror handler, it will be executed when an error occurs. Three arguments are passed to the handler - the error message, the URL of the script and the line, where the error is located.

Simple horizontal text scrolling with Ext Core 3 (marquee replacement)

For one of my projects I needed to implement a line of scrolling text at the top or at the bottom of the browser window. One of the options was to use the non-standard marquee HTML element, which I rejected for obvious reasons. Plus, it didn't work very well - the motion was not smooth and there were too few options to customize its behaviour. So I decided to implement the text scrolling using Javascript.

 There are plenty of code examples on the web. In fact, it's fairly easy, you just need to update the text position using CSS properties. Since I'm used to the ExtJS framework i wrote a simple class using the Ext Core 3 library. Actually I didn't need the high-level features of ExtJS, but I wanted to take advantage of the cross-borswer support, that's why I used the low-level library Ext Core.