JSFiddle - React, Tailwind, and code Playground

HTML

<html>
<head>
<script type="text/javascript">
    function RunDemo()
    {
        var subject = "01234 555 6789";

        for (var i = 1; i <= 10; i++) {
            MethodA(subject, i);
            MethodB(subject, i);
            MethodC(subject, i);
        }
    }

    // OK, OK, OK, OK, OK, OK, OK, OK, OK, OK
    function MethodA(subject, iteration)
    {
        var myRegexp = new RegExp("5", "g");
        var matches = myRegexp.exec(subject);
        AddItem(matches ? "OK" : "no match", "listA");
    }

    // OK, OK, OK, OK, OK, OK, OK, OK, OK, OK
    function MethodB(subject, iteration)
    {
        var myRegexp = /5/;
        var matches = myRegexp.exec(subject);
        AddItem(matches ? "OK" : "no match", "listB");
    }

    // OK, OK, OK, no match, OK, OK, OK, no match, OK, OK (in FireFox and Chrome, IE is fine)
    function MethodC(subject, iteration) {
        var myRegexp = /5/g;
        var matches = myRegexp.exec(subject);
        AddItem((matches ? "OK" : "no match") + myRegexp.lastIndex, "listC");
    }

    function AddItem(itemText, listID) {
        var li = document.createElement("li");
        li.innerHTML = itemText;
        document.getElementById(listID).appendChild(li);
    }   

</script>
</head>
<body onload="RunDemo()">
    <h2>Method A</h2>    
    <ul id="listA"></ul>

    <h2>Method B</h2> 
    <ul id="listB"></ul>

    <h2>Method C</h2> 
    <ul id="listC"></ul>
</body>
</html>