In Below code ion button click textbox is visible then textbox hide or textbox hide the textbox is visible
<script src="Script/jquery-1.3.2.min.js" type="text/javascript"></script>
$('#<%=Button.ClientID%>').click(function () {
if ($('#<%=Textbox1.ClientID%>').is(':visible')) {
$('#<%=Textbox1.ClientID%>').Hide();
}
else {
$('#<%=Textbox1.ClientID%>').show();
}
});