It’s using an HTML <input type=number> element, which requires that the value be a valid floating-point number <https://html.spec.whatwg.org/multipage/common-mi

It’s using an HTML <input type=number> element, which requires that the value be a valid floating-point number <https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#valid-floating-point-number https://html.spec.whatwg.org/multipage/common-microsyntaxes....>. You’ll note from this that exponent notation is allowed, something people are unlikely to expect. For restricting negative numbers, it should probably had the attribute min=0; then negative zero would be the lowest you could go.