"An anti-pattern is a bad design that is worthy of documenting. Examples of anti-patterns in Javascript are the following.

• - Polluting the global namespace by defining a large number of variables in the global context.
• - Passing strings rather than functions to either setTimeout or setInterval, as this triggers the use of eval() internally.
• - Modifying the Object class prototype (this is a particularly bad anti-pattern)
• - Using Javascript in an inline form as this is inflexible.

Knowledge of anti-patterns is critical for success. Once we are able to recognize such anti-patterns, we're able to refactor our code to negate them so that the overall quality of our solutions improves instantly."

- Addy Osmani