HTMLInputElement: size property

The size property of the HTMLInputElement interface defines the number of visible characters displayed. It reflects the <input> element's size attribute.

The size property is relevant to the text, search, tel, email, url, and password input type only. The value is a non-negative integer greater than zero. If omitted or invalid, the value is 20.

const inputElement = document.getElementById("password");
console.log(inputElement.size);
inputElement.size = 12;