make script URL absolute/canonical
function canonical_uri(src,base_path) {
		var absolute_regex = /^\w+\:\/\//;

		// is `src` is protocol-relative (begins with // or ///), prepend protocol
		if (/^\/\/\/?/.test(src)) {
			src = location.protocol + src;
		}
		// is `src` page-relative? (not an absolute URL, and not a domain-relative path, beginning with /)
		else if (!absolute_regex.test(src) && src.charAt(0) != "/") {
			// prepend `base_path`, if any
			src = (base_path || "") + src;
		}
		// make sure to return `src` as absolute
		return absolute_regex.test(src) ? src : ((src.charAt(0) == "/" ? root_domain : root_page) + src);
	}