=====================================前台代码

<input type="button" onclick ="aa();" value="点击" /><script type="text/javascript">function aa() {var bu = document.getElementById("Button1");bu.click();}</script><asp:Button ID="Button1" runat ="server" OnClick ="button1_click" />

=====================================后台代码

protected void button1_click(object sender, EventArgs e){ClientScript.RegisterStartupScript(this.GetType(), "", "<script>alert('对不起，没有此人！！！')</script>");}

访问修饰符是protected或public