Dan Dan - 15 days ago 5
HTML Question

When should I use Inline vs. External Javascript?

I would like to know when I should include external scripts or write them inline with the html code, in terms of performance and ease of maintenance.

What is the general practice for this?

Real-world-scenario - I have several html pages that need client-side form validation. For this I use a jQuery plugin that I include on all these pages. But the question is, do I:


  • write the bits of code that configure this script inline?

  • include all bits in one file that's share among all these html pages?

  • include each bit in a separate external file, one for each html page?



Thanks.

Answer

The rule is simple: All script should be external. Both for maintenance and performance.

(Why performance? Because if the code is separate, it can easier be cached by browsers.)

JavaScript doesn't belong in the HTML code and if it contains special characters (such as <, >) it even creates problems.

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