call protected string on javascript

function logedin() {
var logedin = '[%=LoginCheck %]' ;
if (logedin == "NotLogedin")
{
alert('hi');
showMsgDetails2();
}
}
on aspx.cs page
protected string LoginCheck = string.Empty;

if (Session["clientId"] == null)///For client side checking whetever user in loged in or not. {
lblInivitationMsg.Text = "You must be logged in to use this feature.";
LoginCheck = "NotLogedin";
}