function createDisabledPseudo( disabled ) {

		// Known :disabled false positives: fieldset[disabled] > legend:nth-of-type(n+2) :can-disable
		return function( elem ) {

			// Only certain elements can match :enabled or :disabled
			// https://html.spec.whatwg.org/multipage/scripting.html#selector-enabled
			// https://html.spec.whatwg.org/multipage/scripting.html#selector-disabled
			if ( "form" in elem ) {

				// Check for inherited disabledness on relevant non-disabled elements:
				// * listed form-associated elements in a disabled fieldset
				//   https://html.spec.whatwg.org/multipage/forms.html#category-listed
				//   https://html.spec.whatwg.org/multipage/forms.html#concept-fe-disabled
				// * option elements in a disabled optgroup
				//   https://html.spec.whatwg.org/multipage/forms.html#concept-option-disabled
				// All such elements have a "form" property.
				if ( elem.parentNode && elem.disabled === false ) {

					// Option elements defer to a parent optgroup if present
					if ( "label" in elem ) {
						if ( "label" in elem.parentNode ) {
							return elem.parentNode.disabled === disabled;
						} else {
							return elem.disabled === disabled;
						}
					}

					// Support: IE 6 - 11
					// Use the isDisabled shortcut property to check for disabled fieldset ancestors
					return elem.isDisabled === disabled ||

						// Where there is no isDisabled, check manually
						/* jshint -W018 */
						elem.isDisabled !== !disabled &&
							disabledAncestor( elem ) === disabled;
				}

				return elem.disabled === disabled;

			// Try to winnow out elements that can't be disabled before trusting the disabled property.
			// Some victims get caught in our net (label, legend, menu, track), but it shouldn't
			// even exist on them, let alone have a boolean value.
			} else if ( "label" in elem ) {
				return elem.disabled === disabled;
			}

			// Remaining elements are neither :enabled nor :disabled
			return false;
		};
	}
Returns a function to use in pseudos for :enabled/:disabled
@param {Boolean} disabled true for :disabled; false for :enabled