Check
for valid date using JavaScript. below is the full code.
<head
id="Head1"
runat="server">
<title>Untitled Page</title>
<script
language="javascript"
type="text/javascript">
// Declaring valid date character,
minimum year and maximum year
var dtCh = "/";
var minYear = 1900;
var maxYear = 2100;
function isInteger(s) {
var i;
for (i = 0; i < s.length; i++) {
// Check that current character is
number.
var c = s.charAt(i);
if (((c < "0")
|| (c > "9"))) return
false;
}
// All characters are numbers.
return true;
}
function stripCharsInBag(s, bag) {
var i;
var returnString = "";
// Search through string's
characters one by one.
// If character is not in bag,
append to returnString.
for (i = 0; i < s.length; i++) {
var c = s.charAt(i);
if (bag.indexOf(c) == -1) returnString += c;
}
return returnString;
}
function daysInFebruary(year) {
// February has 29 days in any year
evenly divisible by four,
// EXCEPT for centurial years which
are not also divisible by 400.
return (((year % 4 == 0) && ((!(year % 100 ==
0)) || (year % 400 == 0))) ? 29 : 28);
}
function DaysArray(n) {
for (var i = 1;
i <= n; i++) {
this[i] = 31
if (i == 4 || i == 6 || i == 9 || i == 11) {
this[i] = 30 }
if (i == 2) { this[i]
= 29 }
}
return
this
}
function isDate(dtStr) {
var daysInMonth = DaysArray(12)
var pos1 = dtStr.indexOf(dtCh)
var pos2 = dtStr.indexOf(dtCh, pos1 + 1)
var strMonth = dtStr.substring(0, pos1)
var strDay = dtStr.substring(pos1 + 1, pos2)
var strYear = dtStr.substring(pos2 + 1)
strYr = strYear
if (strDay.charAt(0) ==
"0" && strDay.length > 1)
strDay =
strDay.substring(1)
if (strMonth.charAt(0) ==
"0" && strMonth.length > 1)
strMonth =
strMonth.substring(1)
for (var i = 1;
i <= 3; i++) {
if (strYr.charAt(0) ==
"0" && strYr.length > 1)
strYr =
strYr.substring(1)
}
month =
parseInt(strMonth)
day =
parseInt(strDay)
year =
parseInt(strYr)
if (pos1 == -1 || pos2 == -1) {
alert("The date
format should be : mm/dd/yyyy")
return
false
}
if (strMonth.length < 1 || month < 1 || month >
12) {
alert("Please enter
a valid month")
return
false
}
if (strDay.length < 1 || day < 1 || day > 31 ||
(month == 2 && day > daysInFebruary(year)) || day > daysInMonth[month]) {
alert("Please enter
a valid day")
return
false
}
if (strYear.length != 4 || year == 0 || year <
minYear || year > maxYear) {
alert("Please enter
a valid 4 digit year between " + minYear +
" and " + maxYear)
return
false
}
if (dtStr.indexOf(dtCh, pos2 + 1) != -1 ||
isInteger(stripCharsInBag(dtStr, dtCh)) == false)
{
alert("Please enter
a valid date")
return
false
}
return
true
}
function ValidateForm() {
var dt;
dt =
document.getElementById('txtDate');
if (isDate(dt.value) ==
false) {
dt.focus()
return
false
}
return
true
}
</script>
</head>
<body>
<form id="form2"
runat="server">
<div>
<asp:TextBox
ID="txtDate"
runat="server">
</asp:TextBox>
<asp:Button
ID="Button1"
runat="server"
Text="Button"
OnClientClick="ValidateForm()"
/></div>
</form>
</body>