function advanceXJSChild() {
        var ch = source.charCodeAt(index);

        // { (123) and < (60)
        if (ch !== 123 && ch !== 60) {
            return scanXJSText(['<', '{']);
        }

        return scanPunctuator();
    }
Between XJS opening and closing tags (e.g. <foo>HERE</foo>), anything that
is not another XJS tag and is not an expression wrapped by {} is text.