[jt2190]

Just to add some color to this… values come in from the DOM as strings or numbers or booleans. They go out over HTTP as strings. (These are approximations, I’m going from memory.) The question then becomes: Should I inspect the values or just pass the values along? You can see how a simple form might just collect data and pass it along to a backend, maybe do a bit of cursory inspection of the values to make sure they’re in range. A sophisticated web app, on the other hand, might construct an in-browser-memory model from the data, and so needs to vigorously ensure that the data is correct. In the first case types can be a pain since you’re not telling the compiler anything that isn’t already well understood. In latter case they’re a necessity.