用Page.ClientScript.RegisterClientScriptBlock 和Page.ClientScript.RegisterStartupScript：区别:
1.使用Page.ClientScript.RegisterClientScriptBlock
c#
代码
1 <%@ Page Language=”C#” %>
2 <script runat=”server”>
3 protectedvoid Page_Load(object sender, EventArgs e)
4 {
5 string myScript = @”function AlertHello() { alert(‘Hello ASP.NET’); }”;
6 Page.ClientScript.RegisterClientScriptBlock(this.GetType(),
7 “MyScript”, myScript, true);
8 }
9 </script>
2 <script runat=”server”>
3 protectedvoid Page_Load(object sender, EventArgs e)
4 {
5 string myScript = @”function AlertHello() { alert(‘Hello ASP.NET’); }”;
6 Page.ClientScript.RegisterClientScriptBlock(this.GetType(),
7 “MyScript”, myScript, true);
8 }
9 </script>
运行结果如下：
<html xmlns=”http://www.w3.org/1999/xhtml” ><head><title>Adding JavaScript</title></head><body><form method=”post” action=”JavaScriptPage.aspx” id=”form1”><div><input type=”hidden” name=”__VIEWSTATE”value=”/wEPDwUKMTY3NzE5MjIyMGRkiyYSRMg+bcXi9DiawYlbxndiTDo=” /></div>
<script type=”text/javascript”>
<!--
function AlertHello() { alert(‘Hello ASP.NET’); }// --></script><div><input type=”submit” name=”Button1” value=”Button” onclick=”AlertHello();”id=”Button1” /></div></form></body></html>
2.使用Page.ClientScript.RegisterStartupScript
RegisterStartupScript 方法与RegisterClientScriptBlock方法最大的不同是：RegisterStartupScript 把script放置在 ASP.NET page的底部，而RegisterClientScriptBlock把script放置在ASP.NET page的顶部。
如果你的页面中有如下代码：
<asp:TextBox ID=”TextBox1” Runat=”server”>Hello ASP.NET</asp:TextBox>
c#
protected void Page_Load(object sender, EventArgs e){ string myScript = @”alert(document.forms[0][‘TextBox1’].value);”; Page.ClientScript.RegisterClientScriptBlock(this.GetType(), “MyScript”, myScript, true);
}此页面运行时会报错，原因是JavaScript function先于text box被安放于浏览器。因此JavaScript function找不到TextBox1。
c#
protected void Page_Load(object sender, EventArgs e){ string myScript = @”alert(document.forms[0][‘TextBox1’].value);”; Page.ClientScript.RegisterStartupScript(this.GetType(), “MyScript”, myScript, true);}这段代码把JavaScript function放置于ASP.NET page底部，因此JavaScript运行时它能找到TextBox1。
3.使用Page.ClientScript.RegisterClientScriptInclude
许多开发者把JavaScript放置在.js文件中，使用RegisterClientScriptInclude方法可以注册.js文件中的JavaScript。
c#
string myScript = “myJavaScriptCode.js”Page.ClientScript.RegisterClientScriptInclude(“myKey”, myScript);这将在ASP.NET页面产生如下结构：
<script src=”myJavaScriptCode.js” type=”text/javascript”></script>