In JavaScript, underscores (_) are used as a visual separator for digits in numeric literals to improve readability. However, the underscores are ignored by the JavaScript engine when parsing the number. Therefore, both comparisons in the given code are evaluating to `true` because the numeric values on both sides of the strict equality operator `===` are the same: `100_000_000` is the same as `100000000` and `300_000` is the same as `300000`. The underscores are used only for readability and have no impact on the actual numerical value.