It allows you to view your changes in an actual browser window instantly without a page refresh, reload corresponding browser pages (related to opened file in IDE) and highlight corresponding element. Currently only Google Chrome is supported (extensions for Firefox & Safari are still postponed).
Let’s look at features in detail.
Reload corresponding pages for any opened file in IDE
If you edit your PHP file or Smarty template, it is so boring to switch to the browser and reload tab manually, isn’t it? Forget about it! Just View -> Reload in Browser (of course, you can assign keyboard shortcut (as example, you can assign ⌃+R under Mac OS)).
Completion lookup is also live.
JetBrains Web IDE Team