getElementById问题  急急
<HTML>  
 	 <HEAD>  
 		.... 
 		 <script   language= "javascript "> 				 
    document.getElementById( 'Player ').URL= 'C:\\下载文件\\音乐\\不孤单.mp3 ';					 
 		 </script>  
 	 </HEAD>    
 	 <body>  
 		 <form   id= "Form1 "   method= "post "   runat= "server ">  
 			 <table   id= "tableRealTime ">  
 				 <tr>  
 					 <td>  <ajax:AjaxPanel   id= "AjaxPanelRealTime "   runat= "server ">  
 						 </ajax:AjaxPanel>  
 					 </td>  
 					 <td   align= "right ">  
  <OBJECT   id= "Player "   classid= "CLSID:6BF52A52-394A-11d3-B153-00C04F79FAA6 "   VIEWASTEXT> ..... </OBJECT>  </td>  </tr>  </table>      
 为什么ocument.getElementById( 'Player ').URL总是提示说为空或没有实例呢?   
 半天了没搞定   靠大家了
------解决方案-------------------- <script language= "javascript ">  
  document.getElementById( 'Player ').URL= 'C:\\下载文件\\音乐\\不孤单.mp3 '; 
  </script>  
 放得太靠前了 你的object还没创建好  
 你把上面那句放到最后面 或者 
  <script language= "javascript ">  
 function window.onload() 
 { 
  document.getElementById( 'Player ').URL= 'C:\\下载文件\\音乐\\不孤单.mp3 '; 
 } 
  </script>
------解决方案-------------------- <script>  </script> 内的语句先被执行
------解决方案--------------------表单还没执行,就先执行当然就为空了 
 .... 
  <script language= "javascript ">  
 function fun_onload() 
   {document.getElementById( 'Player ').URL= 'C:\\下载文件\\音乐\\不孤单.mp3 ';} 
  </script>  
  </HEAD>    
  <body onload= "fun_onload() ">  
 ....