They make up the cardiac pacemaker, that is, the natural pacemaker of the heart. In most humans, the concentration of pacemaker cells in the sinoatrial (SA) node is the natural pacemaker, and the resultant rhythm is a sinus rhythm. Sometimes an ectopic pacemaker sets the pace, if the SA node is damaged or if the electrical conduction system of the heart has problems.
Lobo is an extensible all-Java web browser and RIA platform. It supports HTML 4, Javascript (AJAX) and CSS 2 plus direct JavaFX and Java (Swing/AWT) rendering. Cobra is the web browser's renderer API; also a Javascript-aware HTML parser.
JavaScript is a evolving language and there are often new versions of it that are released. As browsers are updated, they start to support these new versions. At the time of this writing, the newest version of JavaScript is/was 1.6. Most browsers don't support JavaScript 1.6, however. Namely, Internet Explorer doesn't support JS1.6, not even the newest IE7 beta.