JSLint: “'HTMLElement' was used before it was defined.”

Question

JSLint: "'HTMLElement' was used before it was defined."

if (element instanceof HTMLElement)

How do I fix this?

Do I have to add an exception or ignore it?

Answer 1

Check "Tolerate misordered definitions".

This works for me if my entire script is:

var e;
if (e instanceof HTMLElement) {
    alert("");
}

and the only checked box is "Tolerate misordered definitions".

The response I get is:

Global HTMLElement, alert, e

This checkbox only seems to apply to identifiers used in the global scope. If this is tried within a function body, JSLint will complain about alert unless you check the box to "Assume console, alert". However the following trick does satisfy JSLint:

var HTMLElement = HTMLElement;
(function () {
    var e;
    if (e instanceof HTMLElement) {
        alert("");
    }
}());

This passes with checkboxes "Assume console, alert", "Tolerate misordered definitions", and "Tolerate missing use strict." I get the response:

Global HTMLElement  
3 'anonymous'()
    Variable e
    Global HTMLElement
    Complexity 2

Definitely a hack; /*global HTMLElement */ is best. Makes sense, though, after reading the JSLint instructions.

Answer 2

Looks like you'll have to add an exception for it. I could not find any of the checkbox options that remove the error.

Answer 3

You can also add HTMLElement to the predefined textbox at the bottom of the JSLint page (if you are using the online validation version).

Since I'm assuming you are in a browser this should be a valid exclusion.

Answer 4

将“ alert”更改为“ window.alert”，并在顶部使用jslint指令/ * jslint browser：true * /。