querySelectorAll with tags/classes

querySelectorAll

window.addEventListener("load", function (){
	alert("Loaded!");

//.querySelectorAll - with tags

var listItems = document.querySelectorAll ("li");
//Becomes an array-like object, check that contains contents with .length
//listItems.length;
for (i = 0; i < listItems.length; i++) {
	listItems[i].style.borderBottom = "2px solid black";
	}

//.querySelectorAll - with classes

var collections = document.querySelectorAll (".datatype");
//collections.length;
for (i = 0; i < collections.length; i++) {
	console.log(collections[i]);
	collections[i].style.color = "red";
	}
});