In my page body, I need to insert this code as the result of an AJAX call:
Loading jQuery
It is pretty safe. Historically, tags are full blocking, hence the second
tag can't get encountered befored the former has finished parsing/excuting. Only problem might be that "modern" browsers tend to load scripts asynchronously and deferred. So to make sure order is correct, use it like this:
Loading jQuery
Using jQuery
However, it's probably a better idea it use dynamic script tag insertion instead of pushing this as HTML string into the DOM. Would be the same story
var scr = document.createElement('script'),
head = document.head || document.getElementsByTagName('head')[0];
scr.src = 'scripts/jquery/core/jquery-1.4.4.js';
scr.async = false; // optionally
head.insertBefore(scr, head.firstChild);