I'm using markdown and I've got some input such as `**test**` which makes the word test appear in bold **test** and I've converted it with html like so"

```
                var converter1 = Markdown.getSanitizingConverter();
                var editor1 = new Markdown.Editor(converter1);
                editor1.run();

                var d = document.getElementById("wmd_input");
                var html = converter1.makeHtml(d.value);
                alert(html);

```

And this alerts `<b>test</b>` the issue is I need to take this value, namely `<b>test</b>` and access this via server side code (asp.net). I tried assigning it to a variable like so:

```
                document.getElementById("Label1").value = html;

```

But it doesn't seem to work, when I go to the code behind it shows `Label1` as being empty.
Is this possible?

Edit
----

I tried to change it to a hidden field same issue:

```
<script type="text/javascript">
                (function () {
                    var converter1 = Markdown.getSanitizingConverter();
                    var editor1 = new Markdown.Editor(converter1);
                    editor1.run();

                    var d = document.getElementById("wmd_input");
                    var html = converter1.makeHtml(d.value);
                    alert(html);

                    document.getElementById('<%= h1.ClientID %>').value = html;
                    var h = document.getElementById('<%= h1.ClientID %>');
                    alert(h.value);
                })();
            </script>

```

The issue I have is I have an asp.net server side button that when clicked I try to do this:

`Label1.Text = h1.Value;`

That is to store the value from the hidden field to a label but this doesnt work. When I put a break point in it shows `h1` is empty `""`....So I'm not sure what event or how to do this so that when I make changes to my textarea `wmd_input` that i should be able to see these changes in my server side code...

Here's my entire asp.net form:

```
<html>
    <head>
        <title>PageDown Demo Page</title>
        <link rel="stylesheet" type="text/css" href="css/demo.css" />
        <script type="text/javascript" src="js/Markdown.Converter.js"></script>
        <script type="text/javascript" src="js/Markdown.Sanitizer.js"></script>
        <script type="text/javascript" src="js/Markdown.Editor.js"></script>
    </head>
    <body>
        <form id="myForm" runat="server">
            <div class="wmd-panel">
                <div id="wmd-button-bar"></div>
                <textarea cols="5" rows="5" id="wmd_input" class="wmd-input" runat="server"></textarea>
                <div id="wmd_preview" class="wmd-panel wmd-preview" runat="server"></div>
            </div>
            <asp:button id="Button1" runat="server" Text="Set" onclick="Button1_Click"></asp:button>
            <asp:button id="Button2" runat="server" Text="Get" onclick="Button2_Click"></asp:button><asp:label id="Label1" runat="server">Label</asp:label>
            <asp:HiddenField ID="h1" runat="server" EnableViewState="true" />
            <script type="text/javascript">
                (function () {
                    var converter1 = Markdown.getSanitizingConverter();
                    var editor1 = new Markdown.Editor(converter1);
                    editor1.run();

                    var d = document.getElementById("wmd_input");
                    var html = converter1.makeHtml(d.value);
                    alert(html);

                    document.getElementById('<%= h1.ClientID %>').value = html;
                    alert(document.getElementById('<%= h1.ClientID %>').value);
                })();
            </script>
        </form>
    </body>
</html>

```
['https://Stackoverflow.com/questions/13237478', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/255446/']
The `asp:Label` tag isn't an input control, so it won't get posted back to the server. I'd suggest using `asp:HiddenField` or `asp:TextBox` instead. (And Adil's point is crucial too, you need to make sure the client ID is actually what you think it is.)

---

Here's a test that works for me. On the first page load, the label shows "initial value", but the alert shows "updated". After postback, the label also shows "updated".

**Edit** Added the client-side update logic inside a client-side event handler.

```
<%@ Page Title="Test" Language="C#" AutoEventWireup="true" %>

<script runat="server">
    void Page_Load()
    {
        l1.Text = h1.Value;
    }
</script>

<html>
<body>
    <form runat="server">
        <asp:HiddenField runat="server" Value="initial value" ID="h1" />
        <asp:Label runat="server" ID="l1" />
        <asp:Button runat="server" Text="do postback" />
    </form>

    <script>
        document.getElementById('<%= Button1.ClientID %>').onclick = function () {
            document.getElementById('<%= h1.ClientID %>').value = 'updated';
            alert(document.getElementById('<%= h1.ClientID %>').value);
        };
    </script>
</body>
</html>

```
you should be able to do what you want to do by using knockoutjs <http://knockoutjs.com/examples/helloWorld.html> You can use element binding.