[jQuery] Multiple Events

I am trying to show and hide a div once some data is processed by the
php.but the second event is not working.What am i doing wrong?

$(document).ready(function(){
//alert("Document is Ready");
$("form#FormID").submit(function(){
//alert("Form is submitted");
$.post("process.php",{keyword:$("#keyword").val()},function(data)
{

//alert("Data Loaded: "+ data );
$("div#display-div").html(data).show();
});
return false;
});
$("button#hide-btn").click(function(){
$("div#display-div").hide();
});
});

<form action="" method="post" id="FormID">
<input type="text" id="keyword" name="keyword"/> <input
type="submit" value="Submit" id="sub" />
</form>
<div id="display-div"></div><input id="hide-btn" type="button"
value="Hide" />