console

• console.log

The better way to see messages from the JavaScript running in the browser is to use the console.log() function and open the console.

• See the documentation of console

Open the console!
<script>

console.log("Hello World");

console.debug("A debug message");
console.info("An info message");
console.warn("A warning");
console.error("This is an error message");

</script>

To open the JavaScript console

• Chrome Mac: Command-Option-J
• Chrome Windows: Ctrl-Shift-J
• Firefox Mac: Command-Option-K
• Firefox Windows: Ctrl-Shift-K
• Internet Explorer: F12
• Safari: Command-Option-C

Run it with Node.JS

Run it in the editor