做webform注意事项 闰年日期

 var year = document.getElementById("Dr_Year");
    var mon = document.getElementById("Dr_Month");
    var day = document.getElementById("Dr_Day");
    document.getElementById("Dr_Year").onchange = function () {
        
        if (mon.value == "2")
        {
            if (this.value % 4 == 0)
            {
                day.options.length = 0;
                for (var i = 1; i < 30; i++)
                {
                    var op = document.createElement("option");
                    op.value = i;
                    op.innerHTML = i;
                    day.appendChild(op);
                }

            }
            else {
                day.options.length = 0;
                for (var i = 1; i < 29; i++) {
                    var op = document.createElement("option");
                    op.value = i;
                    op.innerHTML = i;
                    day.appendChild(op);
                }
            }

        }
    }
    document.getElementById("Dr_Month").onchange = function () {
        
        if (this.value == "2") {
            if (year.value % 4 == 0) {
                day.options.length = 0;
                for (var i = 1; i < 30; i++) {
                    var op = document.createElement("option");
                    op.value = i;
                    op.innerHTML = i;
                    day.appendChild(op);
                }

            }
            else {
                day.options.length = 0;
                for (var i = 1; i < 29; i++) {
                    var op = document.createElement("option");
                    op.value = i;
                    op.innerHTML = i;
                    day.appendChild(op);
                }
            }
        }
        else if (this.value == "1" || this.value == "3" || this.value == "5" || this.value == "7" || this.value == "8" || this.value == "10" || this.value == "12") {
            day.options.length = 0;
            for (var i = 1; i < 32; i++) {
                var op = document.createElement("option");
                op.value = i;
                op.innerHTML = i;
                day.appendChild(op);
            }

        } else {
            day.options.length = 0;
            for (var i = 1; i < 31; i++) {
                var op = document.createElement("option");
                op.value = i;
                op.innerHTML = i;
                day.appendChild(op);
            }
        }
    }

var p1 = document.getElementById("TextBox2");
    var p2 = document.getElementById("TextBox3");

    p1.onkeyup = function () { pwdisok(p1, p2); }
    p2.onkeyup = function () { pwdisok(p1, p2); }

    function pwdisok(pwd1, pwd2) {
        if (pwd1.value != pwd2.value) {
            document.getElementById("pwd_error").innerText = "两次密码不一致！";
            document.getElementById("pwd_error").style.color = "red";
            pwdok = false;
        }
        else {
            document.getElementById("pwd_error").innerText = "正确！";
            document.getElementById("pwd_error").style.color = "green";
            pwdok = true;
        }
    }