Most of the time, when accessing the value of an
HTMLInputElement in an event listener, we use something along the lines of
e.target.value. This is fine in most cases, but when we want the numeric value of an input field, we have to parse it and check if the value is actually valid etc. That can get very annoying, especially when working with larger forms that have many input fields.
What if I told you there's an easier way to get the numeric value from an input field? Meet
HTMLInputElement.valueAsNumber, a handy attribute that will return a numeric value if the input field's value can be converted to a number or
NaN if the conversion is not possible.
const quantityInput = document.getElementById('quantity-input'); let quantity; // Bad: parseFloat() converts the string to a number quantity = parseFloat(quantityInput.value); // Good: returns a numeric value quantity = quantityInput.valueAsNumber;
As usual, this comes with a caveat which is that it only works for
type="number" inputs (although that's probably where you need it the most). On a side note, you can also use
HTMLInputElement.valueAsDate to get a
Date object from a
type="date" input, which might also come in handy in some cases.
A collection of quick tips and tricks to level up your coding skills one step at a time.
Returns an array of HTML elements whose width is larger than that of the viewport's.
Retrieves the value of a CSS rule for the specified element.
Sets the value of a CSS rule for the specified HTML element.