JSFiddle - React, Tailwind, and code Playground

HTML

<form action="#" id="contact">
    <input type="text" class="req"><br>
    <input type="text" class="req"><br>
    <input type="text" class="req"><br>
    <textarea name="" id="" cols="30" rows="10" class="req"></textarea><br>
    <input type="submit">
                    
</form>

JavaScript

document.getElementById('contact').onsubmit = function() {
	var children = this.children;

	for(var i = 0; i < children.length; i++) {
		if (children[i].className == 'req') {
			
			console.log(children[i]); //defined
			console.log(children[i].length); //undefined

		}
	}


	return false;
};