Forms Data Controls :: Passing Two Parameter In Javascript

i am passing two parameter in javascript and open popup window.... but geeting mid value "undefined" here is my code:

<asp:TemplateField HeaderText="comments">
<ItemTemplate>
<a href="javascript:replycomments('<%# Eval("projectid")%>'),('<%# Eval("milestoneserial")%>')">Reply comments</a>
</ItemTemplate>
</asp:TemplateField>

and

function replycomments(id,mid)
{
window.open("replymilestone.aspx?id="+id+"&mid="+mid,"mypage","width=400,height=500,scrollbars=0,menu=0","");
}

this is working fine if i am passing single value like:

<asp:TemplateField HeaderText="comments">
<ItemTemplate>
<a href="javascript:replycomments('<%# Eval("projectid")%>')">Reply comments</a>
</ItemTemplate>
</asp:TemplateField>

and

function replycomments(id)
{
window.open("replymilestone.aspx?id="+id,"mypage","width=400,height=500,scrollbars=0,menu=0","");
}