\documentclass[11pt]{article}

\ifcsname pdfmatch\endcsname

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\usepackage[utf8]{inputenc}

\ifcsname XeTeXinterchartoks\endcsname

\usepackage{fontspec}

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\ifcsname directlua\endcsname

\usepackage{fontspec}

\usepackage{lmodern}

\usepackage{amssymb,amsmath}

\usepackage{graphicx}

\usepackage{fullpage}

\usepackage[keeptemps=all, makestderr, usefamily={javascript}]{pythontex}

\begin{document}

\section*{JavaScript}

\subsection*{Commands}

\javascript{2**8}

\javascriptc{console.log(2**16);}

\javascriptb{console.log(2**32);}

\javascriptv{console.log(2**32);}

\javascripts{\LaTeX\ and then \textcolor{blue}{!{"JavaScript"}} and back to \LaTeX.}

\subsection*{Environments}

Code:

\begin{javascriptcode}

console.log("A string." + " ");

console.log(2**8);

\end{javascriptcode}

Block:

\begin{javascriptblock}

console.log("A string." + " ");

console.log(2**8);

\end{javascriptblock}

Verbatim:

\begin{javascriptverbatim}

console.log("A string." + " ");

console.log(2**8);

\end{javascriptverbatim}

Sub:

\begin{javascriptsub}

\LaTeX\ and then \textcolor{blue}{!{"JavaScript"}} and back to \LaTeX.

\end{javascriptsub}

\section*{JavaScript stderr}

\begin{javascriptblock}[err1][numbers=left]

// Comment

s = "javascript a

\end{javascriptblock}

\stderrpythontex[][breaklines, breakafter=\\/]

\begin{javascriptblock}[err2][numbers=left]

1+;

\end{javascriptblock}

\stderrpythontex[][breaklines, breakafter=\\/]

\begin{javascriptblock}[err3][numbers=left]

// Comment

// Another comment

"a" "b";

\end{javascriptblock}

\stderrpythontex[][breaklines, breakafter=\\/]

\end{document}