Assingning unique id and names?

Assingning unique id and names?

I have a html table with one prototype row. Prototype row has few tds and
each td has input element. I am trying to clone the row and assign unique
ids and names. But in Fire fox new ids and names are assigned properly.
But in IE unique ids and names are not assigned. This logic works fine in
FF. But in IE7 it does not work.
html Table:
<table class="myTable">
<tr class="prototype">
<td>
<label for="myValue1">MY Value ONE:</label><br>
<input class="required email" id="myValue1" type="text" value=""
name="myValue1">
</td>
<td>
<label for="myValue2">MY Value TWO:</label><br>
<input class="required email" id="myValue2" type="text" value=""
name="myValue2">
</td>
<td>
<label for="myValue3">MY Value THREE:</label><br>
<input class="required email" id="myValue3" type="text" value=""
name="myValue3">
</td>
<td>
<label for="myValue4">MY Value FOUR:</label><br>
<input class="required email" id="myValue4" type="text" value=""
name="myValue4">
</td>
</tr>
</table>
JQuery code:
$("#new").click(function(e) {
e.preventDefault();
var d = new Date();
var counter = d.getTime();
var master = $("table.myTable");
var prot = master.find("tr.prototype").clone();
prot.removeClass('prototype');
prot.addClass("contact");
prot.find("#myValue1").attr('id',"myValue1"+counter);
prot.find("#myValue2").attr('id',"myValue2"+counter);
prot.find("#myValue3").attr('id',"myValue3"+counter);
prot.find("#myValue4").attr('id',"myValue4"+counter);
prot.find("#myValue1"+counter).attr('name',"myValue1"+counter);
prot.find("#myValue2"+counter).attr('name',"myValue2"+counter);
prot.find("#myValue3"+counter).attr('name',"myValue3"+counter);
prot.find("#myValue4"+counter).attr('name',"myValue4"+counter);
jQuery('table.myTable tr:last').before(prot);
});
But with the above code unique ids and names are not assigned.am i doing
anything wrong here?
Thanks!