Client side date validation before submit runs

I can figure out how to validate text boxes before the form is submitted to my database.

I need to know how to validate a date before it is submitted to my database because there will be a "type mismatch" as the field in the database is a date field.

Use the isDate function.

i.e.
if not isDate(form.field.value) then
  display error message
end if

Mise Le Meas,

Mighty

Hi,

I'm using isDate successfully in VB Script (on Client-Side error checking on .asp), except when the user types in something like 9/31/01 (30 days has September), in which case I get a string error just for calling isDate, or any of the other date functions.

Does anyone know of a good way to avoid/trap this error and prevent this invalid date entry?

Thanks,
Ray

This should do the trick. I've included javascript and vbscript.
Jon
Javascript:
function validateDate(fieldVal)
{
    fieldVal = trim(fieldVal);
  // Begin
  // Checks for the following valid date formats:
  // mm/dd/yyyy  mm-dd-yyyy
  // Also separates date into month, day, and year variables
  var datePat = /^(\d{1,2})(\/)(\d{1,2})\2(\d{4})$/;
  
  /*
  ^^^^ Information about this string ^^^^
  Ignore first and last '/' it is code for RegExp
  Anything between () will be matched and remembered for later use
  
  ^ matches first input
  $ matches last input
  \ means that the next char after the '\' has a special meaning
  \2 means same thing as second operation in this case its : (\/)
  d means digit, it matches a number from 0 to 9
  {n,m] = matches at least N and at most M occurences. N & M are assumed to be positive
  */
  
  var matchArray = fieldVal.match(datePat); // is the format ok?
  if (matchArray == null)
  {
    errMsg ='Date is not in a valid format.\nUse the mm/dd/yyyy format'
    isError=true
    return false;
  }
  month = matchArray[1]; // parse date into variables
  day = matchArray[3];
  year = matchArray[4];
  //alert(year);
  //alert(year.length);
  if (year.length == 4)
  {
    if (year < 1753)//dates less than January 1 1753 cause an exception in sql server
    {
    errMsg = "Year must be greater than 1752";
    isError=true
    return false;
    }
  }
  if (year.length == 3)
  {
    errMsg = "Year must two or four digits.";
    isError=true
    return false;
  }
  if (month < 1 || month > 12)  // check month range
  {
    errMsg ='Month must be between 1 and 12.'
    isError=true
    return false;
  }
  if (day < 1 || day > 31)
  {
    errMsg ='Day must be between 1 and 31.'
    isError=true
    return false;
  }
  if ((month==4 || month==6 || month==9 || month==11) && day==31)
  {
    errMsg ="Month "+month+" doesn't have 31 days!"
    isError=true
    return false
  }
  if (month == 2)  // check for february 29th
  {
    var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
    if (day>29 || (day==29 && !isleap)) {
    errMsg = "February " + year + " doesn't have " + day + " days!";
    isError=true
    return false;
  }
  
}
return true;  // date is valid
}

vbscript:

<%
Function RegExpValidator(patrn, strng)
    Dim regEx, Match, Matches, RetStr
    Set regEx = new RegExp ' Create a regular expression.
    regEx.Pattern = patrn ' Set pattern.
    regEx.IgnoreCase = True' Set case insensitivity.
    regEx.Global = false' Set global applicability.
    Set Matches = regEx.Execute(strng)' Execute search.
    if Matches.count > 0 then
        RetStr = true
    else
        RetStr = false
    end if
    set Matches = nothing
    set regEx = nothing
    RegExpValidator = RetStr
End Function



function ValidDate(dtDate, sErrorText)
    dim sPatrn, sMonth, sDay, sYear, aDate, bValid, bIsLeap, bPatrnMatch
    dtDate = trim(dtDate)
    sPatrn = "(\d{1,2})(\/)(\d{1,2})\2(\d{4})"
    bPatrnMatch = RegExpValidator(sPatrn,dtDate) '// is the format ok?
    bValid = true
    if bPatrnMatch = true then
        aDate = split(dtDate,"/")
        if ubound(aDate) = 2 then
            sMonth = aDate(0)
            sDay = aDate(1)
            sYear = aDate(2)
            
            if len(sYear) = 4 then
                if sYear < 1753 then ' //dates less than January 1 1753 cause an exception in sql server
                    bValid = false
                    sErrorText = "Year must be greater than 1752"
                else
                    if sMonth < 1 or sMonth > 12 then  '// check month range
                        bValid = false
                        sErrorText = "Month must be between 1 and 12."
                    else
                        if sDay < 1 or sDay > 31 then
                            bValid = false  
                            sErrorText = "Day must be between 1 and 31."
                        else
                            if ((sMonth=4 or sMonth=6 or sMonth=9 or sMonth=11) and sDay=31) then
                                bValid = false
                                sErrorText ="Month " & sMonth & " does not have 31 days!"
                            else
                                if sMonth = 2 then '// check for february 29th
                                    If (sYear Mod 4 = 0 And sYear Mod 100 <> 0) Or sYear Mod 400 = 0 Then
                                        bIsLeap = True
                                    Else
                                        bIsLeap = False
                                    End If
                                    'Response.Write bIsLeap
                                    'Response.Write sDay
                                    
                                    if sDay > 29 or (sDay = 29 and not bIsLeap) then
                                        bValid = false
                                        sErrorText = "February " & sYear & " does not have " & sDay & " days!"
                                    end if
                                end if
                            end if
                        end if
                    end if
                end if
            else
                bValid = false
                sErrorText = "Year must be 4 digits"
            end if
        else
            bValid = false
            sErrorText = "Use the mm/dd/yyyy format"
        end if        
    else
        bValid = false
        sErrorText = "Use the mm/dd/yyyy format"  
    end if
    
    ValidDate = bValid
end function
'response.write ValidDate("5/15/9999", sErrorText) & "<br>"
'Response.Write sErrorText
%>