js验证日期格式

<script language="javascript"> 
function check(){
var a = /^(\d{4})-(\d{2})-(\d{2})$/
if (!a.test(document.getElementById("TextBox1").value)) { 
alert("日期格式不正确!") 
return false 
} 
else 
return true 
} 
</script>

<div>
        <asp:TextBox ID="TextBox1" runat="server" onblur="check();"></asp:TextBox>
        <asp:Button ID="Button1" runat="server" Text="Button" />
 </div>

<div>
        <asp:TextBox ID="TextBox1" runat="server" onblur="check();"></asp:TextBox>
        <asp:Button ID="Button1" runat="server" Text="Button" />
    </div>

function RQcheck(RQ) {
            var date = RQ;
            var result = date.match(/^(\d{1,4})(-|\/)(\d{1,2})\2(\d{1,2})$/);

            if (result == null)
                return false;
            var d = new Date(result[1], result[3] - 1, result[4]);
            return (d.getFullYear() == result[1] && (d.getMonth() + 1) == result[3] && d.getDate() == result[4]);

        }

function CheckAdd() {
            var ret = true;
            if (!RQcheck($id("txt_LLRQ").value)) {
                alert("请输入正确的日期");
                return false;
            }
            return ret;
        }