javascript "script" from external server

I read somewhere that a .js script "served" fro开发者_开发技巧m an external server actually formed part of the page it is used on. Not really being a .js person can someone clarify something for me - please.

I have an application that uses JQuery & php. The Jquery is included via a simple <script> tag and points to the googleapps api Jquery link. The user (member) of the app then loads a page from my server into an empty div on their page via the JQuery ajax call .load() The loaded page is a php script. In some ways you could call it a widget. One aspect of the php script is an e-mail function i.e. the php mail() Am I right is assuming that because the php script is loaded via JQuery/.js the mail() will be processed via their server/mail server i.e. however their "hosts" do it rather than from mine.

Reason I ask concerns scripted e-mail response limits imposed by most hosts in relation to fighting SPAM. Note: the mail() script is not spam in anyway, but a way for the "member" site to gather some information and give feedback.

As alluded to in comments, generally speaking,

• JavaScript is executed by the client (generally a web browser)
  • Regardless of where the source is hosted
• PHP is executed on the server (generally an apache web server)
  • Regardless of where the client request comes from