js 给C#控件控件赋值，后台取不到？

Question

html：

<input type="hidden" runat="server" id="keyTXT" name="keyTXT" />

JS：

$(function () {

            var keyTXT = $(window.parent.document).find('#keyTXT').html();

            document.getElementById('<%=keyTXT.ClientID%>').value= keyTXT; 

        });

后台：

protected void Page_Load(object sender, EventArgs e)

        {

            string hh = keyTXT.Value;

            txtKeywords.Text =hh;

            

        }

上面的 txtKeywords.Text 没值，

页面上有一个按钮（另一个方法的点击事件），按了一下 txtKeywords.Text 有值了。

为什么一开始加载的时候没有，要按某一个按钮才取到呢？

Answer 1

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