None of the above code is working, pls see the sample html below and suggest.
<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
$('tr:lt(3)').find('input[type=radio]').prop('readonly',true);
});
</script>
</head>
<body>
<table border='1'>
<tr>
<td>Test1</td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
</tr>
<tr>
<td>Test2</td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
</tr>
<tr>
<td>Test3</td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
</tr>
<tr>
<td>Test4</td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
</tr>
<tr>
<td>Test5</td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
</tr>
<tr>
<td>Test6</td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
<td><input type="radio"></td>
</tr>
</table>
</body>
</html>