[removed] How do I print a message to the error console?

Question

How can I print a message to the error console, preferably including a variable?

For example, something like:

print(\'x=%d\', x);

Answer 1

To actually answer the question:

console.error('An error occurred!');
console.error('An error occurred! ', 'My variable = ', myVar);
console.error('An error occurred! ' + 'My variable = ' + myVar);

Instead of error, you can also use info, log or warn.