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isDate function - isolate for specific years

I'm using a javascript function that has a regular expression that checks for valid dates. The regular expression works pretty well, howeer, one of the problems is that if a user makes a typo and enters a date way into the future it will cause an error.

For example, say, the user accidentally types in 5/5/9011. That is actually a valid date, but it will cause an error.

So, I was wanting to modify the regular expression to isolate the years from say 1900 to 2100...two hundred years.

I'm not very good with regular expressions, so I was hoping some regex guru couild help with how to isolate those years in the following javascript function that uses the regex.

See the function below.

Thanks for any help.

function isDate(value)
{
   var dateRegEx = new RegExp(/^(?:(?:(?:0?[13578]|1[02])(\/|-)31)|(?:(?:0?[1,3-9]|1[0-2])(\/|-)(?:29|30)))(\/|-)(?:[1-9]\d\d\d|\d[1-9]\d\d|\d\d[1-9]\d|\d\d\d[1-9])$|^(?:(?:0?[1-9]|1[0-2])(\/|-)(?:0?[1-9]|1\d|2[0-8]))(\/|-)(?:[1-9]\d\d\d|\d[1-9]\d\d|\d\d[1-9]\d|\d\d\d[1-9])$|^(0?2(\/|-)29)(\/|-)(?:(?:0[48]00|[13579][26]00|[2468][048]00)|(?:\d\d)?(?:0[48]|[2468][048]|[13579][26]))$/);
 
   if (dateRegEx.test(value))
   {
      return true;
   }
   return false;
}

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ASKER CERTIFIED SOLUTION

cmalakar

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HonorGod

Something like this perhaps?

function isDate( value ) {
  var result = /^[01]?\d\/(([0-2]?\d{1})|([3][0,1]{1}))\/((19\d{2})|(20\d{2})|(2100))$/.test(value)
//  alert( result )
  return result
}

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Erdinç Güngör Çorbacı

This does the trick i guess
^([1-9]|0[1-9]|1[0-9]|2[0-9]|3[01])[/._-](0[1-9]|1[0-2])[/._-](19[0-9][0-9]|20[0-9][0-9])$

HonorGod

Please note, however, that this RegExp allows "invalid" dates, like Feb 31st...

For more detail about JavaScript dates, please take a look at this article:

https://www.experts-exchange.com/A_484.html

Erdinç Güngör Çorbacı

sorry code view is here

^([1-9]|0[1-9]|1[0-9]|2[0-9]|3[01])[/._-](0[1-9]|1[0-2])[/._-](19[0-9][0-9]|20[0-9][0-9])$

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and if you wish to change restriction just change the part i ' underlined

^([1-9]|0[1-9]|1[0-9]|2[0-9]|3[01])[/._-](0[1-9]|1[0-2])[/._-](19[0-9][0-9]|20[0-9][0-9])$

kaufmed

Off-topic, but why not just return the value returned by "test()"?

function isDate(value)
{
   ...
 
   return dateRegEx.test(value);
}

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SOLUTION

hielo

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