Page.ClientScript.RegisterClientScriptBlock 与RegisterClientScriptBlock

最近的项目用到这样一段代码:
//要根据后台取的值初始化页面显示
protected void Page_Load(object sender, EventArgs e)
     {
         if (!IsPostBack)
         {
             GetGovShiftSetInfo();//此方法作用:取数据库数据来设置rbTwo状态
             if (rbTwo.Checked)
             {
                 //Page.RegisterStartupScript("", "<script>istwo();</script>"); //1.0的语法构造,已过时
                 Page.ClientScript.RegisterStartupScript(this.GetType(), "MyScript", "istwo();", true);
             }
         }
     }
----------------------------------------------------------------------------------------
//放在前台的JS:
<script type="text/javascript">
  
      function istwo()
      {
             var   obj1=window.document.getElementById("ctl00_MainContent_panelPmB");
             var   obj2=window.document.getElementById("ctl00_MainContent_panelPmE");
          var   obj3=window.document.getElementById("ctl00_MainContent_lbAmB");
          var   obj4=window.document.getElementById("ctl00_MainContent_lbAmE");
          var   obj5=window.document.getElementById("ctl00_MainContent_panelCard");
          obj1.style.visibility = "hidden";
          obj2.style.visibility = "hidden";
          obj3.style.visibility = "hidden";
          obj4.style.visibility = "hidden";
          obj5.style.visibility = "hidden";
          var no3= parseInt(window.document.getElementById("ctl00_MainContent_txtValue").value);
          if (no3 <   5 || no3 > 500 )
                 {
                     alert("上下班刷卡有效时限:[5-500]分钟内");
               window.document.getElementById("ctl00_MainContent_rbFour").focus();
         window.document.getElementById("ctl00_MainContent_rbFour").checked=true;
         isfour();
             }
               
      }
   --------------------------------------------------------------------------------------------------------
之所以没用Page.ClientScript.RegisterClientScriptBlock而用 Page.ClientScript.RegisterStartupScript是因为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,用RegisterClientScriptBlock会报错,javascript函数不到对象
    
1.使用 Page.ClientScript.RegisterClientScriptBlock
Listing 4-10: Using the RegisterClientScriptBlock method
c#
<%@ Page Language=”C#” %>
<script runat=”server”>
protected void Page_Load(object sender, EventArgs e)
{
string myScript = @”function AlertHello() { alert(‘Hello ASP.NET’); }”;
Page.ClientScript.RegisterClientScriptBlock(
this.GetType(),
“MyScript”, myScript,
true);
}

</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>

Listing 4-11: Improperly using the RegisterClientScriptBlock method
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。

Listing 4-12: Using the RegisterStartupScript method
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。
Listing 4-13: Using the RegisterClientScriptInclude method
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>
posted @ 2010-07-06 18:35  乱炖er  阅读(14714)  评论(0编辑  收藏  举报