ocument.getElementById缺少对象

Question

很多人都有类似的问题，但是似乎都不太一样。代码如下：
function setOverColor(iid, fid){
     document.getElementById(iid).style.color = '#000000';
     switch(iid)
     {
     case 'Info':
                document.getElementById(iid).src = 'Icon_Info_a.gif';       
                break;
            case 'Quick_Start':
document.getElementById(iid).src = 'Icon_Quick_Start_a.gif';       
                break;         
            case 'Advanced':
                document.getElementById(iid).src = 'Icon_Advanced_a.gif';
                break;                  
            //case 'Wireless':
            //   document.getElementById(iid).src = 'Icon_Wireless_a.gif';      
            //   break;       
            //case 'Voice':
            //   document.getElementById(iid).src = 'Icon_Voice_a.gif';      
            //   break;                
            case 'Diagnostic':
                document.getElementById(iid).src = 'Icon_Diagnostic_a.gif';            
                break; 
            case 'Management':
                document.getElementById(iid).src = 'Icon_Management_a.gif';  
                break; 
            default:
             break;
    
     }
     document.getElementById(fid).style.color = '#000000';
    }
    
    function setOutColor(iid, fid){
     if(iid != curCate)
     {
         var name = 'Icon_'.concat(iid);
     document.getElementById(iid).style.color = '#FFFFFF';
     document.getElementById(fid).style.color = '#FFFFFF';      
     document.getElementById(iid).src = name.concat(".gif");
    
        }
    }
      每次到'Managment'的时候都会有问题，说缺少对象，其它几个一样的方法做的，都没问题，实在找不到原因了，望大侠指点。

Answer 1

</script>   
      <table border="0" cellpadding="0" cellspacing="0" width="1800" height="75" bordercolor="#000000" bgcolor='#FFFFFF' valign="top">
      <tbody>
  
    
            <tr>            
            
             <script language="javascript"> 
                <!-- hide              
                //if (window.navigator.appName=='Netscape')
             //    document.writeln("<td width='17%' valign='bottom'><input  id='Logo'  type='image'  src='logo.gif'  onclick='push(this)'/>   </td> ");   
             //else if(window.navigator.appName=='Microsoft Internet Explorer')
             {
                 document.writeln("<td width='210' align='center' valign='center' rowspan='2' bgcolor='#FFFFFF'><input  id='Logo'  type='image'  src='logo.gif'  onclick='push(this)'/>   </td> ");           
             }
             //chenyb added for ENKOM 20100610
             /*Device Info*/
                document.writeln("<td width='100' align='center' bgcolor='#AD2721'>") 
                document.writeln("    <input  id='Info' type='image' src='Icon_Info.gif'  width=30 heigth=30 onmouseover=\"setOverColor('Info', 'info_font')\" onmouseout=\"setOutColor('Info', 'info_font')\" onclick='push(this)'/>") 
                
                document.writeln("</td> ") 
                
                /*Quick Start*/         
                document.writeln("<td width='100' align='center'bgcolor='#AD2721'> ");
                document.writeln("    <input id='Quick_Start' type='image' src='Icon_Quick_Start.gif' width=30 heigth=30 onmouseover=\"setOverColor('Quick_Start', 'qstart_font')\" onmouseout=\"setOutColor('Quick_Start', 'qstart_font')\" onclick='push(this)'>");
                document.writeln("</td>");
                     
                /*Advanced*/       
                document.writeln("<td width='100' align='center' bgcolor='#AD2721'>");
                document.writeln(" <input id='Advanced' type='image' src='Icon_Advanced.gif' width=30 heigth=30 onmouseover=\"setOverColor('Advanced', 'advanced_font')\" onmouseout=\"setOutColor('Advanced', 'advanced_font')\" onclick='push(this)'/>");
                document.writeln("</td>");
                
                /*Wireless*/   
                //document.writeln("<td width='100' align='center'bgcolor='#AD2721'>");
                //document.writeln(" <input id='Wireless' type='image' src='Icon_Wireless.gif'  width=30 heigth=30 onmouseover=\"setOverColor('Wireless', 'wireless_font')\" onmouseout=\"setOutColor('Wireless', 'wireless_font')\" onclick='push(this)'/>");
                //document.writeln("</td>");
                 
                //if((role == 'admin' || role == 'support'))
                //{
                //    /*Voice*/ 
                //    document.writeln(" <td width='100' align='center'bgcolor='#AD2721'>");
                //    document.writeln(" <input id='Voice' type='image' src='Icon_Voice.gif' width=30 heigth=30 onmouseover=\"setOverColor('Voice', 'voice_font')\" onmouseout=\"setOutColor('Voice', 'voice_font')\" onclick='push(this)'/>");
                //    document.writeln("</td>"); 
                //
                //
                //}
                /*Diagnostic*/ 
                document.writeln(" <td width='100' align='center'bgcolor='#AD2721'>");
                document.writeln("  <input id='Diagnostic' type='image' src='Icon_Diagnostic.gif'  width=30 heigth=30 onmouseover=\"setOverColor('Diagnostic', 'diag_font')\" onmouseout=\"setOutColor('Diagnostic', 'diag_font')\" onclick='push(this)'/>");
                document.writeln("</td>");
                /*Management*/ 
                document.writeln("<td width='100' align='center'bgcolor='#AD2721'>");
                document.writeln(" <input id='Management' type='image' src='Icon_Management.gif'  width=30 heigth=30 onmouseover=\"setOverColor('Management', 'manag_font')\" onmouseout=\"setOutColor('Management', 'manag_font')\" onclick='push(this)'/>");
                document.writeln("</td>"); 
                //if(role == admin)      
                    document.writeln("<td bgcolor='#AD2721'>&nbsp</td>"); 
                //else if(role == user)
                //    document.writeln("<td width='385'bgcolor='#AD2721'>&nbsp</td>");
                //else if(role == support)
                //    document.writeln("<td width='385'bgcolor='#AD2721'>&nbsp</td>"); 
                     
                // done hiding -->
             </script>    
            </tr>
            <tr>            <script language="javascript"> 
            <!-- hide
             //chenyb added for ENKOM 20100610
             /*Device Info*/
                document.writeln("<td width='100' align='center'bgcolor='#AD2721'>")                   
                document.writeln("<font color='FFFFFF' id='info_font' size=2px face=\"arial\" onmouseover=\"setOverColor('Info', 'info_font')\" onmouseout=\"setOutColor('Info', 'info_font')\"><strong>Info</strong></font>")   
                document.writeln("</td> ") 
                /*Quick Start*/  
                document.writeln("<td width='100' align='center'bgcolor='#AD2721'>")                   
                document.writeln("<font color='FFFFFF' id='qstart_font' size=2px face=\"arial\" onmouseover=\"setOverColor('Quick_Start', 'qstart_font')\" onmouseout=\"setOutColor('Quick_Start', 'qstart_font')\"><strong>Quick Start</strong></font>")   
                document.writeln("</td> ")
                    
                /*Advanced*/
                document.writeln("<td width='100' align='center'bgcolor='#AD2721'>")                   
                document.writeln("<font color='FFFFFF' id='advanced_font' size=2px face=\"arial\" onmouseover=\"setOverColor('Advanced', 'advanced_font')\" onmouseout=\"setOutColor('Advanced', 'advanced_font')\"><strong>Advanced</strong></font>")   
                document.writeln("</td> ") 
            
               /*Wireless*/
                //document.writeln("<td width='100' align='center'bgcolor='#AD2721'>")                   
                //document.writeln("<font color='FFFFFF' id='wireless_font' size=2px face=\"arial\" onmouseover=\"setOverColor('Wireless', 'wireless_font')\" onmouseout=\"setOutColor('Wireless', 'wireless_font')\"><strong>Wireless</strong></font>")   
                //document.writeln("</td> ")    
                //if((role == 'admin' || role == 'support'))
                //{
                //    /*Voice*/
                //    document.writeln("<td width='100' align='center'  bgcolor='#AD2721'>")                   
                //    document.writeln("<font color='FFFFFF' id='voice_font' size=2px face=\"arial\" onmouseover=\"setOverColor('Voice', 'voice_font')\" onmouseout=\"setOutColor('Voice', 'voice_font')\" ><strong>Voice<strong></font>")   
                //    document.writeln("</td> ")                                  
                //}
                /*Diagnostic*/ 
                document.writeln("<td width='100' align='center'bgcolor='#AD2721'>")                   
                document.writeln("<font color='FFFFFF' id='diag_font' size=2px face=\"arial\" onmouseover=\"setOverColor('Diagnostic', 'diag_font')\" onmouseout=\"setOutColor('Diagnostic', 'diag_font')\"><strong>Diagnostic</strong></font>")   
                document.writeln("</td> ") 
                /*Managment*/   
                document.writeln("<td width='100' align='center'bgcolor='#AD2721'>")                   
                document.writeln("<font color='FFFFFF' id='manag_font' size=2px face=\"arial\" onmouseover=\"setOverColor('Managment', 'manag_font')\" onmouseout=\"setOutColor('Managment','manag_font')\"><strong>Management</strong></font>")   
                document.writeln("</td> ")                                                                //if(role == admin)      
                    document.writeln("<td bgcolor='#AD2721'>&nbsp</td>"); 
                //else if(role == user)
                //    document.writeln("<td width='385'bgcolor='#AD2721'>&nbsp</td>");
                //else if(role == support)
                //   document.writeln("<td width='385'bgcolor='#AD2721'>&nbsp</td>");                                                        // done hiding -->       
            </script>

Answer 2

  case 'Management':
  document.getElementById(iid).src = 'Icon_Management_a.gif';   如果按你说的，那么有这么几种可能：1）我们得保证html的dom加载完毕，再执行js。你可能在dom未加载完毕就执行了你的js代码  2）你的dom对象中没有src属性

Answer 3

我运行了你这个代码行: 38
错误: 'curCate' 未定义
报了这个错误！你应该知道什么原因吧！

Answer 4

'Management'拼错了，有几个地方写成'Managment'了。