JSFiddle - React, Tailwind, and code Playground

HTML

<html xmlns="http://www.w3.org/1999/xhtml">
    
<head>
    
    <title> </title>
    
    <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery/jquery-1.4.1.js"></script>
    
</head>
    
<body>

    <input name="txtName" type="text" id="txtName" />

    <input type="submit" name="btnSave" value="Save"  id="btnSave" />


</body>
</html>

JavaScript

$('#btnSave').click(function(e)
{
        
        var reportRecipients = "A,a, a,  a  ,";
        checkDuplicate(reportRecipients );
 
});


function checkDuplicate(reportRecipients )
{
     if (reportRecipients.length > 1) 
        {
           
            var recipientsArray = reportRecipients.split(',');
            var newUniqueArray = [];
            
            alert('Expected Alert 1');
            
            for (a in recipientsArray) 
            {
               
                var email =$.trim(recipientsArray[a]);
         
                if ( $.inArray(email,newUniqueArray) == -1 ) 
                {
                    newUniqueArray.push(email);
                }
 
            }
 
            alert('Expected Alert 2');
            
            return false;
 
        }
}