Following the introduction of Internet Explorer 7 for Windows XP SP2 and Windows Server 2003 in October 2006, and then in November 2006 and January 2007, concomitantly with the business and consumer launches of Windows Vista, Microsoft debuted the next stage into the evolution of IE. At this point in time, early builds of Internet Explorer 8 are being dogfooded internally at Microsoft, but the Redmond company failed to deliver even the most anodyne details related to the browser's evolution, outside of a general perspective over IE8 dropped at MIX07.

Still, there are bits and pieces that slip through, just crumbs from the Internet Explorer 8. In this context, John Hrvatin, Program Manager Internet Explorer, revealed that for IE8 Microsoft is focusing strongly on resolving the current memory leakage problems associated with IE7 and IE6. Measures have been taken to mitigate the problems in the currently available versions of the Microsoft proprietary browser, but there is room for improvement.

"These memory leaks often occur as a result of circular references between Jscript objects and objects within IE's DOM (document object model). Since the Jscript engine and IE have independent memory management schemes, each side can't see the entire cycle of these circular references. Internet Explorer 7 improved the situation by releasing all references to Jscript objects attached to the DOM tree when IE navigates away from that page. This allows the Jscript engine to then garbage collect those Jscript objects and recover that memory. We've also made the same changes in IE6 on Windows XP SP2," Hrvatin explained.

Despite the work poured into IE7 and IE6, the browser versions, taking down the markup still causes IE to drop anything that is not connected to the tree. Users might have experienced memory leaks with Internet Explorer when keeping websites opened for prolonged periods of time. If the website has not been optimized to steer clear of leak patterns, Internet Explorer will cause memory usage to grow and grow delivering a heavy impact on the overall performance of the machine. "So no, it's not perfect, but we're also continuing to invest in improvements for future versions of IE", Hrvatin promised.

But before Internet Explorer 8 drops, at this time it is expected in late 2008, early 2009, Microsoft recommended two tools designed to help developers deal with memory leaks. "Drip and sIEve (joint SourceFourge site) are two such tools. Many of you may already be familiar with them, but a little extra visibility never hurts. Both applications host Trident - IE's rendering engine - and add detection of memory leak patterns. They let you track memory and DOM usage while using a site and then detect any leaks when you navigate away from that page. Drip is an open source project under the BSD license. Based on Drip, sIEve improves the usability in a few ways including non-modal dialogs and a real-time graph of DOM usage instead of memory usage", Hrvatin added.