控件ID问题

　有时候运行程序的时候，可能ID会变，使你对原来ID的操作没用．当你发现这种问题时，可以查看页面的source，看看ID变没变．如下代码（不能运行，只是给示范用，比较乱）：

<% @ Page Language="C#" AutoEventWireup="true" CodeFile="ProjectIntro.aspx.cs" Inherits="DMaP.UserInterface.ProjectIntro"  %>
<% @ Register Src="ProjectIntro1.ascx" TagName="intro" TagPrefix="uc1"  %>
<% @ Register Src="ProjectIntro2.ascx" TagName="intro" TagPrefix="uc2"  %>
< html  xmlns ="http://www.w3.org/1999/xhtml"   >
< head  runat ="server" >
     < title >
         < asp:localize  runat ="server"  text ="<%$ Resources:PageTitle %>" ></ asp:localize >
     </ title >
     < link  href ="css/normal.css"  type ="text/css"  rel ="stylesheet" />
     < link  href ="styles/ProjectIntro.css"  type ="text/css"  rel ="stylesheet" />
</ head >
< script  language ="javascript"  type ="text/javascript" >
function menu1MouseOver()
{
    document.getElementById('intro1').className = "InputShow";
    document.getElementById('intro2').className = "InputHidden";
    document.getElementById('menu1').className = "menuSelect";
    document.getElementById('menu2').className = "menuRelease";
    document.getElementById('lblIntro2').className = "fontMouseRealse";
    document.getElementById('lblIntro1').className = "fontMouseOver";
    return false;
}

function menu2MouseOver()
{
    document.getElementById('intro1').className = "InputHidden";
    document.getElementById('intro2').className = "InputShow";
    document.getElementById('menu1').className = "menuRelease";
    document.getElementById('menu2').className = "menuSelect";
    document.getElementById('lblIntro2').className = "fontMouseOver";
    document.getElementById('lblIntro1').className = "fontMouseRealse";              
    return false;
}
</ script >
< body  onload ="javascript:menu1MouseOver()" >
     < form  id ="Form1"  runat ="server"  method ="post" >
         < table  cellspacing ="0"  cellpadding ="0"  border ="0"  class ="MainTable" >
             < tr >
                 < td >
                     < div  id ="divBreadCrumb" >
                         < asp:Image  ID ="Image1"  runat ="server"  ImageUrl ="~/image/arrows.gif"   />
                         < span  class ="CurrentPage" >
                             < asp:Localize  ID ="Localize3"  runat ="server"  Text ="<%$ Resources:DMaP, CurrentPage  %>" ></ asp:Localize ></ span >
                         < span  class ="CurrentPageInfo" >
                             < asp:Localize  ID ="Localize4"  runat ="server"  Text ="<%$ Resources: ProjectIntro  %>" ></ asp:Localize ></ span >
                     </ div >
                 </ td >
             </ tr >
             < tr >< td > &nbsp; </ td ></ tr >
             < tr >
                 < td >
                     < table  cellspacing ="0"  cellpadding ="0"  style ="width:100%; padding: 5px; " >
                         < tr >
                             < td  id ="menu1"  class ="menuSelect"  onmousemove ="menu1MouseOver()"  onclick ="menu1MouseOver()" >                                 
                                 < asp:Label  ID ="lblIntro1"  runat ="server"  Text ="<%$ Resources: lbIntro1  %>"  CssClass ="fontMouseOver" ></ asp:Label >
                             </ td >
                             < td  id ="menu2"  class ="menuRelease"  onmousemove ="menu2MouseOver()"  onclick ="menu2MouseOver()" >
                                 < asp:Label  ID ="lblIntro2"  runat ="server"  Text ="<%$ Resources: lbIntro2  %>" ></ asp:Label >
                             </ td >
                             < td  id ="menu3"  style ="border-bottom:solid 1px #95BEE4; width:40%;" > &nbsp; </ td >
                         </ tr >
                     </ table >
                 </ td >
             </ tr >
             < tr  id ="intro1"  runat ="server" >
                 < td  class ="mainIntroText" >
                     < uc1:intro  ID ="ProIntro1"  runat ="server"   />
                 </ td >
             </ tr >
             < tr  id ="intro2"  runat ="server" >
                 < td  class ="mainIntroText" >
                     < uc2:intro  ID ="ProIntro2"  runat ="server"   />
                 </ td >
             </ tr >             
         </ table >
     </ form >
</ body >
</ html >

这代码的作用是通过MouseOver事件进行交替显示，但如果把这代码放到<asp:Content ></asp:Content>中的话，会自动在有　runat="server"　的控件的ID前加上"ctl00_ContentPlaceHolder1_"，你把代码放到<asp:WizardStep></asp:Wizard>,则会加上"Wizard1_"．