<!-- How to Import a JS File --><script src="pathToFile/fileName.js"></script><!-- How to Write a Function -->function functionName() { // body of the function}<!-- How to Change CSS of an ID on the Page -->document.getElementById("idName").style.property = 'value';<!-- How to Run a Function on Button Click -->< button onclick="functionName()">buttonName</button><!-- Create a Variable -->var nameOfVariable = value;<!-- How to Use an If-Statement -->if (condition) { // do this if the condition is true}<!-- How to Set Text of an HTML Element in JS -->document.getElementById("idName").innerHTML = 'newTextInElt'