\begin{alltt}
<script>alert("a")</script>
Hello
There <em></em> '<>' \textbackslash{}emph \textbar{} \textbackslash{}emph
\end{alltt}
\begin{alltt}
<script>alert("a")</script>
Hello
There <em></em> '<>' \textbackslash{}emph \textbar{} \textbackslash{}emph
\end{alltt}