How to find which child element is invalid in an HTML5 form

Question

Is there a way to find which child elements in the form is invalid using the html5 automatic form validation?

I know we can check element by element, by calling checkValidity() method. What I'm seeking is, if there's a shorter way.

For example,

var contactForm = document.getElementById('contact-form');
if (contactForm.checkValidity() == false) {
    // something like contactForm.getInvalidChildren() and apply 
    // different style and error message based on the child type
}

Answer 1

I found this method in MDN which satisfies my requirement. But I'm not sure if it's the best way to do this.

var contactForm = document.getElementById('contact-form');
if (contactForm.checkValidity() == false) {
    var list = contactForm.querySelectorAll(':invalid');
    for (var item of list) {
        item.setAttribute("style", "background-color: red;")
    }
}