It is bad if you have a large amount of JavaScript being used across multiple pages. In that case, the JavaScript should be in an external, compressed, and cachable file and if your site has very heavy traffic you should make use of a CDN.However, if you have a small amount of JavaScript the saving of putting it in an external file might be negated by the fact you need to make an additional HTTP request to retrieve it. In this instance it would be more efficient to keep the JavaScript in your page.