JavaScript to the operating system's API with superuser privileges. These flaws have affected major browsers including Firefox, Internet Explorer, and Safari. Plugins, such as video players, Adobe Flash, and the wide range of ActiveX controls enabled by default in Microsoft Internet Explorer, may also have flaws exploitable via JavaScript (such flaws have been exploited in the past). In Windows Vista, Microsoft has attempted to contain the risks of bugs such as buffer overflows by running the Internet Explorer process with limited privileges. Google Chrome similarly confines its page renderers to their own "sandbox". Web browsers are capable of running JavaScript outside
Chakra (JScript engine) Chrome (with V8), and Opera (with Carakan). On March 8, 2011, Microsoft published results showing the 32-bit Internet Explorer 9 to be faster than Safari, Firefox (with TraceMonkey), Chrome, and Opera. March 2011 performance tests for ZDNet concluded that Internet Explorer 9 (32-bit), Chrome 10, and Firefox 4 release candidate were "pretty evenly matched." In 2012, subsequent versions of Chakra, such as the version included in Internet Explorer 10, introduced additional performance changes, including JIT compilation on x64 and ARM architectures, and optimizations related to floating point math and garbage collection. At the Last Call JSCONF in 2015, Microsoft announced