not work with JQuery in ASP.NET

I have a CheckBox

<asp:CheckBox ID="CheckBox2" runat="server" Text="Type of Change"></asp:CheckBox>

and a funcion, that work correctly, however only the alert appears "Work" but the checkbox not It updates

function Checks() {
    var value1 = "false"

    if (value1 == "false") {
        alert("Work");
        $("CheckBox2").prop('checked', true);
    } else {
        alert("False");
    }
}

When loading the page you can see the checkbox checked without any problem

$("CheckBox2").prop('checked', true);

    function Checks() {
        var value1 = "false"

        if (value1 == "false") {
            alert("Work");
        } else {
            alert("False");
        }
    }

I think the checkbox should be updated somehow when entering the if