The below code is check-in entering string is current date or previous date, the previous date did not include Saturday and Sunday.
ASPX Page
  1. <aspx:TextBox runat="server" id="txtvalid" ></asp:TextBox>
  2. lt;asp:Button ID="btnsave" Text="Create User" runat="server" OnClientClick="dateValidation(this);"/>
Script
  1. function dateValidation(evt) {
  2. var d = new date();
  3. var n = d.getDay();
  4. var text = document.getElementById("txtvalid").value;
  5. var today = new date();
  6. var dd = today.getDate();
  7. var mm = today.getmonth() + 1;
  8. var yyyy = today.getFullYear();
  9. if (dd < 10) {
  10. dd = '0' + dd
  11. }
  12. if (mm < 10) {
  13. mm = '0' + mm
  14. }
  15. today = dd + '/' + mm + '/' + yyyy
  16. if (n = 1)
  17. var yest = dd - 3;
  18. else
  19. var yest = dd - 1;
  20. var yestrday = yest + '/' + mm + '/' + yyyy
  21. if (text != today && (text != yesterday)) {
  22. alert('Please Enter current date or previous date'
  23. }
  24. }
  25. }
Thanks Sreejesh