Check for valid date using JavaScript. below is the full code.
  1. <head id="Head1" runat="server">
  2. <title>Untitled Page</title>
  3. <script language="javascript" type="text/javascript">
  4. // Declaring valid date character, minimum year and maximum year
  5. var dtCh = "/";
  6. var minYear = 1900;
  7. var maxYear = 2100;
  9. function isInteger(s) {
  10. var i;
  11. for (i = 0; i < s.length; i++) {
  12. // Check that current character is number.
  13. var c = s.charAt(i);
  14. if (((c < "0") || (c > "9"))) return false;
  15. }
  16. // All characters are numbers.
  17. return true;
  18. }
  20. function stripCharsInBag(s, bag) {
  21. var i;
  22. var returnString = "";
  23. // Search through string's characters one by one.
  25. // If character is not in bag, append to returnString.
  26. for (i = 0; i < s.length; i++) {
  27. var c = s.charAt(i);
  28. if (bag.indexOf(c) == -1) returnString += c;
  29. }
  30. return returnString;
  31. }
  33. function daysInFebruary(year) {
  34. // February has 29 days in any year evenly divisible by four,
  35. // EXCEPT for centurial years which are not also divisible by 400.
  36. return (((year % 4 == 0) && ((!(year % 100 == 0)) || (year % 400 == 0))) ? 29 : 28);
  37. }
  39. function DaysArray(n) {
  40. for (var i = 1; i <= n; i++) {
  41. this[i] = 31
  42. if (i == 4 || i == 6 || i == 9 || i == 11) { this[i] = 30 }
  43. if (i == 2) { this[i] = 29 }
  44. }
  45. return this
  46. }
  48. function isDate(dtStr) {
  49. var daysInMonth = DaysArray(12)
  50. var pos1 = dtStr.indexOf(dtCh)
  51. var pos2 = dtStr.indexOf(dtCh, pos1 + 1)
  52. var strMonth = dtStr.substring(0, pos1)
  53. var strDay = dtStr.substring(pos1 + 1, pos2)
  54. var strYear = dtStr.substring(pos2 + 1)
  55. strYr = strYear
  56. if (strDay.charAt(0) == "0" && strDay.length > 1)
  57. strDaystrDay = strDay.substring(1)
  58. if (strMonth.charAt(0) == "0" && strMonth.length > 1)
  59. strMonthstrMonth = strMonth.substring(1)
  60. for (var i = 1; i <= 3; i++) {
  61. if (strYr.charAt(0) == "0" && strYr.length > 1)
  62. strYrstrYr = strYr.substring(1)
  63. }
  64. month = parseInt(strMonth)
  66. day = parseInt(strDay)
  67. year = parseInt(strYr)
  68. if (pos1 == -1 || pos2 == -1) {
  69. alert("The date format should be : mm/dd/yyyy")
  70. return false
  71. }
  72. if (strMonth.length < 1 || month < 1 || month > 12) {
  73. alert("Please enter a valid month")
  74. return false
  75. }
  76. if (strDay.length < 1 || day < 1 || day > 31 || (month == 2 && day > daysInFebruary(year)) || day > daysInMonth[month]) {
  77. alert("Please enter a valid day")
  78. return false
  79. }
  80. if (strYear.length != 4 || year == 0 || year < minYear || year > maxYear) {
  81. alert("Please enter a valid 4 digit year between " + minYear + " and " + maxYear)
  82. return false
  83. }
  84. if (dtStr.indexOf(dtCh, pos2 + 1) != -1 || isInteger(stripCharsInBag(dtStr, dtCh)) == false) {
  85. alert("Please enter a valid date")
  86. return false
  87. }
  88. return true
  89. }
  91. function ValidateForm() {
  92. var dt;
  93. dt = document.getElementById('txtDate');
  94. if (isDate(dt.value) == false) {
  95. dt.focus()
  96. return false
  97. }
  98. return true
  99. }
  100. </script>
  101. </head>
  103. <body>
  104. <form id="form2" runat="server">
  105. <div>
  106. <asp:TextBox ID="txtDate" runat="server">
  107. </asp:TextBox>
  108. <asp:Button ID="Button1" runat="server" Text="Button" OnClientClick="ValidateForm()" />
  109. </div>
  110. </form>
  111. </body>