_getParentForm() {
        if (!AutoNumericHelper.isUndefined(this.domElement.form)) return this.domElement.form; // This catches input elements outside the form element

        if (this.domElement.tagName.toLowerCase() === 'body') {
            return null;
        }

        let node = this.domElement;
        let tagName;
        do {
            node = node.parentNode;
            if (AutoNumericHelper.isNull(node)) {
                // Special case when using templates with frameworks like Vue.js, where the input element can be 'detached' when initializing the DOM structure
                return null;
            }

            if (node.tagName) {
                tagName = node.tagName.toLowerCase();
            } else {
                tagName = '';
            }

            if (tagName === 'body') {
                // Get out of the loop if we get up to the `<body>` element
                break;
            }
        } while (tagName !== 'form');

        if (tagName === 'form') {
            return node;
        } else {
            return null;
        }
    }
Returns a reference to the parent <form> element if it exists, otherwise return `null`.

@returns {HTMLFormElement|null}
@private