Javascript: Function To Validate Date Format DD/MM/YYYY

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Pleas

function validateDateDDMMYYY(DateOfBirth)
{

var Char1 = DateOfBirth.charAt(2);
var Char2 = DateOfBirth.charAt(5);
// alert(Char1); alert(Char2);

var flag =false;

if ( Char1 =='/' && Char2 == '/' )
{
// alert ('valid positions of non numeric characters.');
flag = true;
}
else
{
// alert('invalid position of non numeric symbols');
flag =false;
}

var day;
var month;
var year;

day = DateOfBirth.substring(0,2);
month = DateOfBirth.substring(3,5);
year = DateOfBirth.substring(6,10);

// alert(day); alert(month);alert(year);
if( validDay(day) && validMonth(month) && validYear(year) && (flag ==true) )
{
// alert(' Valid Date')
return true;
}
else
{
alert('Invalid Date Format: Please enter DD/MM/YYYY for Date of Birth!');
return false;
}

} // end func

function IsNumeric(sText)
{
var ValidChars = "0123456789.";
var IsNumber=true;
var Char;

for (i = 0; i < sText.length && IsNumber == true; i++) { Char = sText.charAt(i); if (ValidChars.indexOf(Char) == -1) { IsNumber = false; } } return IsNumber; } // end func function validDay(day) { if ( IsNumeric(day) ) { if( day >0 && day <32) { return true; } else { return false; } } else { return false; } }// end func function validMonth(month) { if ( IsNumeric(month) ) { if( month >0 && month <13) { return true; } else { return false; } } else { return false; } }// end func function validYear(year) { var d = new Date(); var currentYear = d.getFullYear(); if( year.length!= 4) { return false; } if ( IsNumeric(year) ) { if( year >0 && year <=currentYear)
{
return true;
}
else
{
return false;
}

}
else
{
return false;
}

}// end func