JSFiddle - React, Tailwind, and code Playground

HTML

<div id="parameters">
    <h2>Parametri</h2>
    <div><label for="N">N</label><input type="text" id="N" name="N" value="" /></div>
<div><label for="M">M</label><input type="text" id="M" name="M" value="" /></div>
</div>
<input type="button" id="buttontest" value="Test" onclick="javascript:document.testDiv()" />
<div id="result">
    <h2>Rezultati</h2>
    <div><label for="result1">for (i = 0; i &lt; times; i++) x = x &gt;&gt; 1;</label><input type="text" id="result1" name="result1" value="" readonly="readonly" /></div>
<div><label for="result2">for (i = 0; i &lt; times; i++) x = x / 2;</label><input type="text" id="result2" value="" name="result2" readonly="readonly" /></div>
</div>

CSS

h2{ font-weight: bold}
div#result{ background-color: #DDDDDD }
div#parameters { background-color: #DDDDDD }

label { width:300px; display:inline-block; zoom:1}

JavaScript

document.testDiv = function () {
        var result1 = document.getElementById("result1");
        var result2 = document.getElementById("result2");
        var inputN= document.getElementById("N");
        var inputM= document.getElementById("M");
    
        var t1, t2, t11, t12, x, i, j;
        var times = inputN.value;
        var times2 = inputM.value;
        t1 = 0; t2 = 0;
        for (j = 0; j < times2; j++) {
            x = Math.random() * 100000;
            t11 = new Date();
            for (i = 0; i < times; i++) x = x >> 1;
            t12 = new Date();
            t1 += (t12 - t11);

            t11 = new Date();
            for (i = 0; i < times; i++) x = x / 2;
            t12 = new Date();
            t2 += (t12 - t11);
        }
        result1.value = t1 + " ms";
        result2.value = t2 + " ms";
    };