.getAttribute()

element.getAttribute(name);

Note: Attributes differ from properties on an element. A property is simply a property on the object, which can hold any type, while an attribute is always a string. For a variety of interactive properties, such as checked or value of an input, you probably want to simply access the property, eg. let isChecked = checkboxElement.checked; or let val = inputElement.value;.

<input type="checkbox">

let value = document.query("input").getAttribute("type");