JSFiddle - React, Tailwind, and code Playground

HTML

<div class="programlisting"><pre class="scilabcode"><span class="scilabcomment">// copy - paste in scilab</span>

<span class="scilabfkeyword">function</span> <span class="scilabfunctionid">example_mode</span><span class="scilabopenclose">(</span><span class="scilabinputoutputargs">level_mode</span><span class="scilabopenclose">)</span>
 <span class="scilabcommand">mode</span><span class="scilabopenclose">(</span><span class="scilabinputoutputargs">level_mode</span><span class="scilabopenclose">)</span>
 <span class="scilabid">a</span> <span class="scilaboperator">=</span> <span class="scilabnumber">3</span>
 <a class="scilabcommand" href="disp.html">disp</a><span class="scilabopenclose">(</span><span class="scilabcommand">mode</span><span class="scilabopenclose">(</span><span class="scilabopenclose">)</span><span class="scilabopenclose">)</span><span class="scilabdefault">;</span>
<span class="scilabfkeyword">endfunction</span>

<span class="scilabcommand">mode</span><span class="scilabopenclose">(</span><span class="scilabnumber">2</span><span class="scilabopenclose">)</span>

JavaScript

if (!window.x) {
    x = {};
}

// http://stackoverflow.com/questions/5669448/get-selected-texts-html-in-div
x.Selector = {};
x.Selector.getSelected = function() {
    var html = "";
    if (typeof window.getSelection != "undefined") {
        var sel = window.getSelection();
        if (sel.rangeCount) {
            var container = document.createElement("div");
            for (var i = 0, len = sel.rangeCount; i < len; ++i) {
                container.appendChild(sel.getRangeAt(i).cloneContents());
            }
            html = container.innerHTML;
        }
    } else if (typeof document.selection != "undefined") {
        if (document.selection.type == "Text") {
            html = document.selection.createRange().htmlText;
        }
    }
    return html;
}

$(document).ready(function() {
    $(document).bind("mouseup", function() {
        var mytext = x.Selector.getSelected();
        alert(mytext);
console.log(mytext);
    });
});