- Review
- null and undefined
- while loops
- Using JavaScript on the web
- document.write
- Running an html file in Cloud 9
- prompt
- Comments
- Single line
- multi-line
- Using comments for thinking/planning
You can run JavaScript on a website by loading it on a page using a <script> tag.
For now, don't worry too much about the details of this webpage. We are using this more as an easy way to get user input for a program.
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="index.js"></script>
</head>
<body>
</body>
</html>You can write content to the webpage using the document.write method in a JavaScript file running inside a website.
document.write("Welcome to my new homepage. It is still under construction.");
To run an html file in Cloud 9, just have the html file open and click the run button.
This will run a webserver, and a link to the server location should appear in a window at the bottom of the screen.
When you click that link you can either open the webpage in a new window by choosing open or open it in a tab in Cloud 9 by choosing open in preview.
The prompt function will show a dialog with the provided text prompting the user for input.
When the user clicks OK on the prompt dialog, it will return the input provided by the user.
var name = prompt("What is your name?");
document.write("Greetings " + name + " it is nice to meet you.");Comments in JavaScript can be single line comments or multi-line comments.
// This is a single line comment
// A single line comment starts with two slashes, and anything after the slashes is the comment
var name = "Jared"; // A single line comment can even be on the same line as running code
// var number = 42; But if the comment starts before the code then the code does not run
/* Multi-line comments are started with a slash star and end with a star slash
Anything that appears between those delimiters is part of the comment
var number = 42
*/
var number = 42;