jquery empty text box event

I can make a div hide when a textbox is in use like this:

开发者_StackOverflow  $("#text-box").**keyup**(function(){
    $("#container").hide();
  });

....but how do I show the div again when the text box is empty:

 $("#text-box").**what-event-goes-here??**(function(){
    $("#container").show();
  });

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EDIT: the correct event is 'keyup'

$("#text-box").bind("keyup", function() { 
   if ($(this).val() == "")
     $("#container").show();
});

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if container is by default hidden then u can also use below code

$("#text-box").bind("keyup", function() { 
   if ($(this).val() =='')
     $("#container").show();
});