My javascript code modifies some properties, visibility included. After postback, some properties stuck, others are "forgotten". Here I try to change the Text property of a textbox and the visibility property of a label to 'hidden'. After postback, the text is preserved, but the label is shown. I would very much like to keep the label hidden after the postback. The same occurs with the 'display' CSS property. Or, if I try to hide a <div>. Any help would be very much appreciated:
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ShowHide.aspx.cs" Inherits="WebApplication1.ShowHide" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
<script type="text/javascript" language="javascript">
function ShowHide()
{
debugger;
var txt = document.getElementById('txtNumber');
txt.value='4';
var lbl = document.getElementById('lblShowHide');
if(lbl.style.visibility == 'hidden')
{
lbl.style.visibility = '';
}
else
{
lbl.style.visibility = 'hidden';
}
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Label ID="lblNumber" runat="server" Text="Enter Number" />
<asp:TextBox ID="txtNumber" runat="server" Text="5" />
<asp:Label ID="lblShowHide" runat="server" Text="Show" />
<input id="btnChangeByJS" type="button" value="HTML Change by JavaScript" onclick="ShowHide();" />
<asp:Button ID="cmdSubmit" runat="server" Text="ASP Submit" />
<asp:HiddenField ID="hfShowHide" runat="server" />
</div>
</form>
</body>
</html>
Thank you!