Unexpected Token with Scripts using Jade and Express

I am new to Jade and I am having some problems with the Scripts.

In some of them, I get Unexpected Token errors... this is one example:

script
    $(document).ready({

        $('#answer').keyup(function(e) {
            $('#preview').html($('#answer').val());
        });

    });

This should work fine in common HTML, but with Jade it says:

Uncaught SyntaxError: Unexpected token (

Do I have to use any special syntax with Jade?

Thanks.