<!doctype html>
<html>
<head>
    <title>Complete JavaScript Course</title>
</head>
<body>
    <textarea name="txtarea" rows=2 cols=50></textarea> <button>Get Emails</button>
    <textarea name="txtarea2" rows=2 cols=50></textarea>
    <script>
        const firstArea = document.querySelector("textarea[name='txtarea']");
        const secArea = document.querySelector("textarea[name='txtarea2']");
        document.querySelector("button").addEventListener("click", lookUp);
        function lookUp() {
            const rawTxt = firstArea.value;
            const eData = rawTxt.match(/([a-zA-Z0-9._-]+@[a-zA-Z0-9._-]+\.[a-zA-Z0-9._-]+)/gi);
            const holder = [];
            for (let x = 0; x < eData.length; x++) {
                if (holder.indexOf(eData[x]) == -1) {
                    holder.push(eData[x]);
                }
            }
            secArea.value = holder.join(',');
        }
    </script>

</body>
</html>
