Required Fields validation for date format as dd-mm-yy in java script:

<script language="javascript">


function check()

{
var value = document.getElementById('<%=txtstart.ClientID%>').value;
var value1=document.getElementById('<%=txtend.ClientID%>').value;
var valTime = new RegExp("(0[1-9]|[12][0-9]|3[01])[- ](0[1-9]|1[012])[- ](19|20)");

var sdate=document.getElementById('<%=txtstart.ClientID%>');
var edate=document.getElementById('<%=txtend.ClientID%>');

if(value==null||value=="")

 {

  alert("Please enter  Start Date");
 
  document.getElementById('<%=txtstart.ClientID%>').focus();
       return (false);

 }

  if(value1==null||value1=="")

 {

  alert("Please enter  End Date");
 
  document.getElementById('<%=txtend.ClientID%>').focus();
       return (false);

 }


      if (sdate.value.match(valTime) == null)
      {
         alert("Please enter correct date format as dd-mm-yyyy");
         return (false);
      }




    return (true);


 }

</script>

<asp:Button ID="btnsub" runat="server" Text="Submit" OnClientClick=" return check()"
                                                                    OnClick="btnsub_Click" CssClass="btn_bg" />