Socket.io doesn't send disconnect event to NodeJS in IE8/9 - node.js

Question

I use NodeJS with socket.io for my chat application. When client refreshes/closes the window or navigates to different URL I need client to emit "disconnect" event to NodeJS server. All works nice with excpetion of IE8/9. When refresh happens "disconnect" event is not send to server so server is not aware that this particular client is no longer connected.
I managed to use:
window.onbeforeunload = function(e) {
socket.disconnect();
};
and this takes care of clicking back/forward button and then the server is informed about client disconnecting. Refreshing the page or closing the tab however doesn't send disconnect to server. It seems that refreshing the page is too quick so the socket.disconnect() has no chance of executing. It seems so as if I do alert like below, client pauses for alert window and server receives disconnect message.
window.onbeforeunload = function(e) {
socket.disconnect();
alert("hey watchout!");
};
Now, is there any way to make IE8/9 send disconnect event to NodeJS when page is refreshed?

Answer 1

You can send information back and forth and find the time of the last reply, compare it to now and if the difference is greater than a number, disconnect the client, then reconnect when the client starts sending again.
You can use something like:
On client:
socket.on('ping',function(){socket.emit('pong',(new Date()).getTime());});
On server:
socketReferences = new Array();
io.on('connection',function(socket){
socketReferences.push(socket);
socket.on('pong',function(data){
if(new Date()).getTime()>5000){
// disconnect code here
}
});
});
setInterval(function(){
for(socket in socketReferences)
socketReferences[socket].emit('ping','');
},700);