Window.console

The Window.console property returns a reference to the console object, which provides methods for logging information to the browser's console. These methods are intended for debugging purposes only and should not be relied on for presenting information to end users.

The first example logs text to the console.

console.log("An error occurred while loading the content");

The next example logs an object to the console, with the object's fields expandable using disclosure widgets:

console.dir(someObject);

See Usage in console for more thorough examples.