jquery
function add(id) 
{
	$(function()
	{
        	//$("#"+id).clone(true).insertAfter('#'+id); // check after() 

	$("#"+id).clone(true).insertAfter('#'+id).find("input").each(function(data) {
		var s = $(this).attr("name");

		var t = s.replace('myid','insertID');
		$(this).attr("name",s);
		});

	});
}

<table width="400" border="1" id='myTable'>
<tr id='k1'>
<td onclick="addTr('k1')">Insert</td>
<td>ww</td>
<td><input type='text' value='98'/  name='myid[1][6]'></td>
</tr>
<tr id='k2'>
<td onclick="addTr('k2')">Insert</td>
<td>ff</td>
<td><input type='text' value='1400'  name='myid[2][6]'></td>
</tr>
<tr id='k3'>
<td onclick="addTr('k3')">Insert</td>
<td>gfhgf</td>
<td><input type='text' value='45'/ name='myid[3][6]'></td>
</tr>
</table>

var count =  0 ;
function add(id) 
{
	$(function()
	{
	$("#"+id).clone(true).insertAfter('#'+id).find("input").attr("name","insertid["+count+"][]");
	   count++;
	});

}