Q:

How to add a line break after each dynamically created checkbox?

Here's the code for the dynamically created checkboxes. How do I add line breaks to the code so that I have one checkbox per line? I tried to do document.createElement("br") and appending it after get.appendChild(label) but it didn't work.
function setCheckboxes(browser) {
    var get = document.getElementById("get");

    if (browser == "courses") {
        for (var i = 1; i < coursesGetKeys.length; i++) {
            var checkBox = document.createElement("input");
            var label = document.createElement("label");
            checkBox.type = "checkbox";
            checkBox.value = coursesGetKeys[i];
            checkBox.name = "r";
            label.textContent = setOpt(coursesGetKeys[i], browser);
            get.appendChild(checkBox);
            get.appendChild(label);
            //label.appendChild(document.createTextNode(setOpt(validCoursesKeys[i], dataset)));
        }
    }

    if (browser == "rooms") {
        for (var i = 1; i < validRoomsKeys.length; i++) {
            var checkBox = document.createElement("input");
            var label = document.createElement("label");
            checkBox.type = "checkbox";
            checkBox.value = validRoomsKeys[i];
            checkBox.name = "r";
            label.textContent = setOpt(validRoomsKeys[i], browser);
            get.appendChild(checkBox);
            get.appendChild(label);
            //label.appendChild(document.createTextNode(setOpt(validCoursesKeys[i], dataset)));
        }
    }
};

A:

You already know how to create an input:
var checkBox = document.createElement("input");

and how to append it:
get.appendChild(checkBox); // get is the parent element you selected at the top of your code

So your first hunch was correct, you can also do this:
var br = document.createElement("br");
get.appendChild(br);

which creates a br element, and then also appends it to the "get" parent.

