window.onload = function() {
	var headers = document.getElementsByTagName("h1");//grab all h1's
	for(i=0; i<headers.length; i++) {//loop through the h1's
	var elem = getNextElement(headers[i].nextSibling);//look for the next sibling of the h1
	
	//apply these styles to the selected elements
	elem.style.color = "red";
	elem.style.backgroundColor = "black";
	}
}
//getNextElement function
function getNextElement(node) {
	if(node.nodeType == 1){
		return node;
		}
	if(node.nextSibling) {
		return getNextElement(node.nextSibling)
		}
	return null;
}

Usage of the getNextElement function. Very basic usage to pick out the h1 tags, then change the properties of the next element(not node).

Usage of getNextElement Function

js, DOM

JavaScript