Due to the abundance of flaws, security holes, and incompatibilities in the JavaScript interpreters in all the major browsers , not to mention the annoying abuses of JavaScript by amateur authors and by sites like GeoCities, I am reluctant to use or recommend JavaScript for serious communication. There are numerous JavaScript-related flaws in the Opera browser. At one time I had discovered several and provided descriptions of them here. The descriptions are still here, but the collection is no longer being actively maintained. Each flaw is demonstrated on a separate page, which you can reach with the links below.
Some mathematical computations produce incorrect results.
N 3.10 JavaScript falsely reports radio buttons as checked. N 3.10 Setting a radio button with JavaScript does not unselect other buttons in the same group. The Math.round method produces incorrect results. 3.20 Date object constructors do not initialize objects properly. The with statement does not work properly for some objects.