data8/_includes/js/print.html

<!-- Include nbinteract for interactive widgets -->
<script src="https://printjs-4de6.kxcdn.com/print.min.js" async></script>
<script>
printContent = () => {
    // MathJax displays a second version of any math for assistive devices etc.
    // This prevents double-rendering in the PDF output.
    var ignoreAssistList = [];
    assistives = document.querySelectorAll('.MathJax_Display span.MJX_Assistive_MathML').forEach((element, index) => {
        var thisId = 'MathJax-assistive-' + index.toString();
        element.setAttribute('id', thisId);
        ignoreAssistList.push(thisId)
    });

    // Print the actual content object
    printJS({
        printable: 'textbook_content',
        type: 'html',
        css: "{{ site.css_url | relative_url }}/styles.css",
        scanStyles: false,
        targetStyles: ["*"],
        ignoreElements: ignoreAssistList
    })
};

initPrint = () => {
    document.querySelector('#interact-button-print').addEventListener('click', printContent)
}

initFunction(initPrint)
</script>