求在c#程序中将文本框取得焦点的javascript

Question

private void Page_Load(object sender, System.EventArgs e)
{  if(!Page.IsPostBack)
   {
userid.Text="";
pwd.Text="";
msg.Text="";

   if(!Page.IsStartupScriptRegistered("myscript"))
   {
Page.RegisterStartupScript("myscript","<script Language=\"Javascript\">document.Form1.userid.focus();</script>");
}
    }// 在此处放置用户代码以初始化页面
}

Answer 1

first,make sure of the control's clientID,and then you can do like this way:
Page.RegisterStartupScript("focusres","<script language=javascript>document.form1['txtbox1'].focus();</script>");

Answer 2

static public bool SetFocus(System.Web.UI.Control control)
{
if (HttpContext.Current.Request.Browser.JavaScript)
{
control.Page.RegisterStartupScript("sf","<script language='javascript'>document.forms[0]." +
control.ClientID +".focus();</script>");
return true;
}
return false;
}而后控制SetFocus(控件名)

Answer 3

Page.RegisterStartupScript与Response.Write有什么区别？
请介绍一谢，非常感谢