template_header
template_header — allows you to append Scrips and CSS to the site's <head>
Summary
template_header($tags);
Usage
// add external css file
template_header('http://example.com/assets/bootstrap.css');
// add external js file
template_header('http://example.com/assets/bootstrap.js');
//add in-line js to head
template_header('<script>alert("Hi");</script>');