what are the disadvantages of adding <script> in tpl file

Question

I want to add in theme template . Are there any disadvantages using scripts inside a drupal template tpl.php file.?

Answer 1

It depends:

• Is it your own theme? (sub-theme from contributed theme usually) - If not, you better not hack it. (you changes will be deleted next time you will update the theme)
• Assumes above as yes, do you have many templates files?
• Is it a "root" template? like html or page or is it more in depth like node, search-result and so on?

The disadvantages:

• You must copy-paste this script to all overriding template files if template suggestions, suggest another variation of the template. (e.g page.tpl.php, page--front.tpl.php, page--node--article.tpl.php
• You must make sure manually, this script does not appear twice in different places.
• Take into consideration this script will go in any page users can see. (e.g search results page, taxonomy index, node pages, views pages, user login/registration pages.) - If it is not necessary in all pages, this is bad practice.
• Performance wise, the JS aggregation feature will not work for this script, so this means one more request from the client.