asp.net怎么获取js变量的值_ASP.NET

asp.net如何获取js变量的值
js:
<script language="javascript" type="text/javascript">

var w=screen.width;
var h=screen.height;
alert( "当前显示器分辨率 "+w+ "* "+h);

</script>

在js 中定义了w和h两个变量，分别取得显示器分辨率的宽和长，想要把这两个变量的值传递到.aspx页面的page_load中，如何实现
protected void Page_Load(object sender, EventArgs e)
{

TextBox1.Text = "height = " + Request.Params["h"].ToString();

TextBox2.Text = "width = " + Request.Params["w"].ToString();
｝
这样做不行，提示 w 和h 是空值

------解决方案--------------------------------------------------------
你想在后台拿肯定，前台要送过去，要不提交表单，要不ajax请求，作为表单或参数提交到后台，才能这么写~
------解决方案--------------------------------------------------------

HTML code

    <script src="js/jquery-1.5.2.min.js" type="text/javascript"></script>    <script type="text/javascript">        $(function() {            $.post("CacheDemo.aspx", { "strWidth": window.screen.width,"strHeight":window.screen.height }, function(data, status) {                if (status == "success") {                }            });});    </script>
------解决方案--------------------------------------------------------
js:
  <script language="javascript" type="text/javascript">
  
 var w=screen.width; 
 var h=screen.height; 
 //alert( "当前显示器分辨率 "+w+ "* "+h); 
 document.getElementById("w").value = w;
 document.getElementById("h").value = h;

 </script>
页面：
 <asp:hiddenfield id="w" runat="server" value=""></asp:hiddenfield>
 <asp:hiddenfield id="h" runat="server" value=""></asp:hiddenfield>

page_load中，
  protected void Page_Load(object sender, EventArgs e)
 {
  
 TextBox1.Text = "height = " + h.value;
  
 TextBox2.Text = "width = " + w.value;
 ｝