To check that date in textbox should be less then current date.

function checkDate()
{
			var date1 = document.getElementById("<%=txtDOI.ClientID%>");
            var today = new Date();
            var dd = today.getDate();
            var mm = today.getMonth() + 1; //January is 0!
            var yyyy = today.getFullYear();
			var StartDate = date1.value.split("/");
            {
                if (parseInt(eval(StartDate[2])) > yyyy) 
				{
                    alert("Enter Date is more then current date!");
                    date1.focus();
                    return (false);
                }
                else if (parseInt(eval(StartDate[2])) == yyyy) 
				{
                    if (parseInt(StartDate[1]) > mm) 
					{
                        alert("Enter Date is more then current date!");
                        date1.focus();
                        return (false);
                    }
                    else if (parseInt(eval(StartDate[1])) == mm) 
					{
                        if (parseInt(StartDate[0]) > dd) 
						{
                            alert("Enter Date is more then current date!");
                            date1.focus();
                            return (false);
                        }
                        else if (parseInt(eval(StartDate[0])) > dd) 
						{
                            alert("Enter Date is more then current date!");
                            date1.focus();
                            return (false);
                        }
                    }
                }
            }
			}