JSFiddle - React, Tailwind, and code Playground

HTML

<html xmlns="http://www.w3.org/1999/xhtml">
<head><title>
 
</title></head>
<body>
 
    <form method="post" action="FormattingTest.aspx" id="form1">
        

    <div style="width:100px">
     <ul>
     <li>A</li>
     <li>B</li>
     <li>B</li>
     <li>C</li>
     <li>C</li>
     <li>C</li>
     <li>D</li>
     </ul>
    </div>
    <input id="bntSubmit" type="button" value="submit" class="submitButton" />
    </form>
        
</body>
    
     <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.1/jquery.js">
     
</script> 
</html>

JavaScript

$('.submitButton').click( function() {
    alert('Begin');
   /* var previousVal = 'Initial';
    
    $('ul li').each(function (i,item)
    {
        var currentVal = $(item).text();
        if( currentVal == previousVal)
        {
            $(item).remove();
        }
        previousVal = currentVal;
    });
    
    alert('End');
    return false;*/
});