debug.js is an embeddable JavaScript debugger for web development.
It allows you to debug easily without the F12 Tools. The library has useful features such as logging, DOM element inspector, screen measure, file viewer, command-line, original script interpreter for automated testing, etc.
Logging:
<!DOCTYPE html>
<html>
<head>
<script src="debug.js"></script>
<script>
function foo() {
log('button was clicked');
}
</script>
</head>
<body>
<button onclick="foo();">BUTTON</button>
</body>
</html>
For more information on how to use, see: https://debugjs.net/