<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<title></title>
<style>
table {
border: 1px red solid;
}
tr {
width: 100%;
height: 40px;
}
td {
width: 100px;
border: 1px darkred solid;
}
</style>
</head>
<body>
<table id="tb" cellspacing='0'>
<tr class='tr1'>
<td>1</td>
<td>1</td>
</tr>
<tr class='tr1'>
<td>2</td>
<td>2</td>
</tr>
<tr class='tr1'>
<td>3</td>
<td>3</td>
</tr>
<tr class='tr1'>
<td>4</td>
<td>4</td>
</tr>
</table>
<script>
var tr = document.querySelectorAll('.tr1');
var td = document.querySelectorAll('td');
var table = document.querySelectorAll('#tb')
for (let i = 0; i < tr.length; i++) {
tr[i].onclick = function () {
tr.forEach((el) => {
el.style.backgroundColor = 'white';
})
tr[i].style.backgroundColor = 'blue';
}
}
</script>
</body>
</html>
