MVC3 Share DropDownList or Hidden value with multiple forms
===

I have a jQuery dialog that holds multiple tabs, each tab contains a form, and the jQuery dialog contains a DropDownList with a "global" value that will be shared across all the tabs/forms.   

The key is "Site", which is set either by a hidden field or by a drop down list depending on the result from the controller.

This is probably a very trivial task but I can't figure out how to do it (Still new to MVC3, JavaScript and web programming in general). I could grab the value in JavaScript by doing `var value = $('#Site').val();` but I don't know how to send it to the controller since I can't save JS variables in C# variables but only vice versa. I use this command to submit the form: `$('#' + tabid).submit();`

Code:

    <div id='jquery-dialog' title="Create new">

	  @if (ViewBag.SiteList == null)
      {
        @Html.Hidden("Site", Request.Params["ForSite"])
      }
      else
      {
        @Html.DropDownList("Site", (SelectList)ViewBag.SiteList)
      }

      <div id="tabs">
        <ul>
          <li><a href="#tab0">Tab 0</a></li>
          <li><a href="#tab1">Tab 1</a></li>
        </ul>

        @using (Ajax.BeginForm("Create", null, new AjaxOptions() { HttpMethod = "POST" }, new { id = "tab0" }))
        {
	      <div id="tab0">
		    This is Tab 0
          </div>
        }

        @using (Ajax.BeginForm("Create", null, new AjaxOptions() { HttpMethod = "POST" }, new { id = "tab1" }))
        {
	      <div id="tab1">
            This is Tab 1
          </div>
        }
      </div>
    </div>