LinkButton - Not firing click event in second time

http://theway2sharepoint.blogspot.com/2012/03/linkbutton-not-firing-click-event-in.html

 

<script type="text/javascript">

function setFormSubmitToFalse()
{
_spFormOnSubmitCalled = false;
return true;
}

</script>

<asp:LinkButton ID="btnDate" runat="server" HtmlEncode="false" CommandName="Download" CommandArgument="<%# ((GridViewRow) Container).RowIndex %>" Text='<%# Eval("Date")%>' OnClientClick="javascript:setFormSubmitToFalse();"></asp:LinkButton> 

Get querysytring parameter with javascript

function getQuerystring(key, default_)
{
  if (default_==null) default_="";
  key = key.replace(/[\[]/,"\\\[").replace(/[\]]/,"\\\]");
  var regex = new RegExp("[\\?&]"+key+"=([^&#]*)");
  var qs = regex.exec(window.location.href);
  if(qs == null)
    return default_;
  else
    return qs[1];
}

Reference:http://www.bloggingdeveloper.com/post/JavaScript-QueryString-ParseGet-QueryString-with-Client-Side-JavaScript.aspx