function isDate(dateStr){
	//function checks for valid dates in the form of dd/mm/yyyy
	
	var maxDays = new Array(31,28,31,30,31,30,31,31,30,31,30,31);
	
	//check for leapyear, if true then make max days in feb 29
	if((year % 4 == 0) && ( (!(year % 100 == 0)) || (year % 400 == 0))){
		maxDays[2] = 29;
	}
	
	var day = dateStr.substring(0,2);	
	var month = dateStr.substring(3,5);	
	var year = dateStr.substring(6,10);	
	var split1 = dateStr.substring(2,3);
	var split2 = dateStr.substring(5,6);
			
	if(split1 != '/'){ return false;}
	if(split2 != '/'){ return false;}
	
	if((!day.match(/^\d{2}$/)) || (!month.match(/^\d{2}$/)) || (!year.match(/^\d{4}$/))){				
		return false;
	}
	
	if((year < 1900) || (year > 2050)){
			return false;
		}
	
	if((month < 0) || (month > 12)){
		return false;
	}
	
	if((day < 0) || (day > maxDays[month-1])){
		return false;
	} 
	
	return true;
}