Aside from the fact that it's basically blogspam which does a poor job of explaining common JavaScript idioms, articles like this are dangerous because of what they <i>don't</i> say.<p>In (2), for example, they suggest using the short-circuit feature of the || operator in assignments, and mention that a null, undefined or empty string value on the left will make the assignment fall through to the value on the right hand side. What this fails to mention is that any value that converts to false will trigger the fall-through: this includes 0, false, and NaN and well as the values already mentioned.<p>(9) is really pernicious since it neither explains the real uses of the arguments object, nor mentions how it can screw up the public interface your functions provide. For example, if a function has no named arguments it will have a length property of 0. This can screw up all kinds of handy stuff like higher-order programming.