var firstnames = ["Hook", "Rumpelstiltskin", "Belle", "Emma", "Regina", "Aurora", "Elsa", "Anna", "Snow White", "Prince Charming", "Cora", "Zelena", "August", "Mulan", "Graham", "Discord", "Will", "Robin Hood", "Jiminy Cricket", "Henry", "Neal", "Red"];
var lastnames = ["Adams", "Bowden", "Conway", "Darden", "Edwards", "Flynn", "Gilliam", "Holiday", "Ingram", "Johnson", "Kraemer", "Hunter", "McDonald", "Nichols", "Pierce", "Sawyer", "Saunders", "Schmidt", "Schroeder", "Smith", "Douglas", "Ward", "Watson", "Williams", "Winters"];
var count = 10;
function createRowFromHTML(htmlString) {
var table = document.createElement('tbody');
table.innerHTML = htmlString.trim();
return table.firstChild;
}
function Randomizer() {
// clear old names
document.getElementsByTagName("tbody")[0].innerHTML = "";
for (var i = 1; i < count; i++) {
nameone = firstnames[Math.floor(Math.random() * firstnames.length)];
nametwo = lastnames[Math.floor(Math.random() * lastnames.length)];
message = "<tr><td>" + nameone + "</td><td>" + nametwo + "</td></tr>";
var row = window.createRowFromHTML(message)
document.getElementsByTagName("tbody")[0].appendChild(row);
}
}
<center>
<input type="button" value="Generate database" onclick="Randomizer();">
<table id="names">
<thead>
<tr>
<th>First Name</th>
<th>Last Name</th>
</tr>
</thead>
<tbody>
</tbody>
</table>
</center>