JavaScript: Show/Hide field

$(document).ready(function () {
    if ($("#ID").val() == "1") {
        $("#Other").show();
    }
    else {
        $("#Other").hide();
    }
});
function ShowHideOther() {
    if ($("#ID").val() == "1") {
        $("#Other").show();
    }
    else {
        $("#Other").val("");
        $("#Other").hide();
    }
}

Add

new { onchange = "ShowHideOther()" }

to the drop-down list definition in the view