Previously we have introduced how Medium achieved loading images lazily, basically what they did was using lots of HTML tags and CSSs to change the images at different stage. It needs lots of code to do this. With the high demand of this feature for resource consumption and performance consideration, Chrome is now working on a feature to provide native support for loading images/iframes lazily. This feature is named lazyload.lazyload will allow three values:auto: the default behavior of lazyload attribute is not altered (user agent decides)on: the feature lazyload is turned on which ...

JavaScript debug is a very troublesome thing in web application development. Because many web browsers will not notify you if there is any error in the JavaScript codes you write. They just silently fail and block the following codes execution. In order to debug JavaScript codes, we need a good log mechanism which will help us log the error information,, we often need to log errors in JavaScript codes to server for debug purpose in a production web application,What should we do?The first thought comes into our mind may be using AJAX, since it involves client server communication and we al...

Qt library is an excellent GUI library for C++ programmers developed by Nokia and now is an open source project. Often, we may use QPainter to draw strings, lines or images on a QWidget. We can override the QWidget's paintEvent() method when we want to use QPianter object to draw something on a QWidget.If we want to save the items drawn on QWidget as image for later reference, what can we do? We can save a QWidget as an image. Here is the code for achieving this:QPixmap pixmap(this->size());this->render(&pixmap);pixmap.save("test.png");Quite simple, right? Yes, these are all the code...