http://www.redips.net/javascript/date-validation/
function isDate(txtDate) {
var objDate, // date object initialized from the txtDate string
mSeconds, // txtDate in milliseconds
day, // day
month, // month
year; // year
// date length should be 10 characters (no more no less)
if (txtDate.length !== 10) {
return false;
}
// third and sixth character should be '/'
if (txtDate.substring(2, 3) !== '/' || txtDate.substring(5, 6) !== '/') {
return false;
}
// extract month, day and year from the txtDate (expected format is mm/dd/yyyy)
// subtraction will cast variables to integer implicitly (needed
// for !== comparing)
month = txtDate.substring(0, 2) - 1; // because months in JS start from 0
day = txtDate.substring(3, 5) - 0;
year = txtDate.substring(6, 10) - 0;
// test year range
if (year < 1000 || year > 3000) {
return false;
}
// convert txtDate to milliseconds
mSeconds = (new Date(year, month, day)).getTime();
// initialize Date() object from calculated milliseconds
objDate = new Date();
objDate.setTime(mSeconds);
// compare input date and parts from Date() object
// if difference exists then date isn't valid
if (objDate.getFullYear() !== year ||
objDate.getMonth() !== month ||
objDate.getDate() !== day) {
return false;
}
// otherwise return true
return true;
} |
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