Possible duplicate of:
should-i-link-to-google-apis-cloud-for-js-libraries
also many other discussions, including:
Where do you incl
keep in mind that google jsapi loads the scripts only after the document itself is loaded.
So, if (for example) you are using jquery's $(document).ready() in your web app, you'll have to switch to google.setOnLoadCallback().
$(document).ready()
google.setOnLoadCallback()