<!DOCTYPE html>
<html>
<head>
<style>
td, th {
border: 1px solid black;
}
</style>
</head>
<body>
<table id="myTable" style="border-collapse:collapse;">
<tr>
<th>Month</th>
<th>Savings</th>
</tr>
<tr>
<td>January</td>
<td>$100</td>
</tr>
<tr>
<td>February</td>
<td>$150</td>
</tr>
</table>
<br>
<button type="button" onclick="myFunction()">Return border collapse</button>
<script>
function myFunction() {
alert(document.getElementById("myTable").style.borderCollapse);
}
</script>
</body>
</html>