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
Firefox page loads. In the final category, conformance, it was determined that Firefox had "strong" conformance for JavaScript and HTML5. In conclusion, "Tom's Hardware" determined that Firefox was the best browser for Windows 7 OS, but that it only narrowly beat Google Chrome. In June 2013, "Tom's Hardware" again performance tested Firefox 22, Chrome 27, Opera 12, and Internet Explorer 10. They found that Firefox slightly edged out the other browsers in their "performance" index, which examined wait times, JavaScript execution speed, HTML5/CSS3 rendering, and hardware acceleration performance. Firefox also scored the highest on the "non-performance" index, which measured memory efficiency,