求高手指教.........在线等回复
我现在做个图片焦点切换,用js来写    
 代码如下:   
  <!DOCTYPE   html   PUBLIC    "-//W3C//DTD   XHTML   1.0   Transitional//EN "    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd ">  
  <html   xmlns= "http://www.w3.org/1999/xhtml ">  
  <head>  
  <meta   http-equiv= "Content-Type "   content= "text/html;   charset=gb2312 "   />  
  <title> 焦点切换 </title>  
  <script   language= "JavaScript "   type= "text/JavaScript ">  
 var   img_1   =   new   Image(); 
 img_1.src   =    "F:\焦点切换\页签小图2\页签小图2\bg_4.gif "; 
 var   img_2   =   new   Image(); 
 img_2.src   =    "F:\焦点切换\页签小图2\页签小图2\cj_1.gif "; 
 var   img_3   =   new   Image(); 
 img_3.src   =    "F:\焦点切换\页签小图2\页签小图2\cj_2.gif "; 
 var   img_4   =   new   Image(); 
 img_4.src   =    "F:\焦点切换\页签小图2\页签小图2\cq_1.gif "; 
 var   img_5   =   new   Image(); 
 img_5.src   =    "F:\焦点切换\页签小图2\页签小图2\cq_2.gif "; 
 var   img_6   =   new   Image(); 
 img_6.src   =    "F:\焦点切换\页签小图2\页签小图2\cs_1.gif "; 
 var   img_7   =   new   Image(); 
 img_7.src   =    "F:\焦点切换\页签小图2\页签小图2\cs_2.gif "; 
 var   img_8   =   new   Image(); 
 img_8.src   =    "F:\焦点切换\页签小图2\页签小图2\dj_1.gif "; 
 var   img_9   =   new   Image(); 
 img_9.src   =    "F:\焦点切换\页签小图2\页签小图2\dj_2.gif "; 
 var   img_a   =   new   Image(); 
 img_a.src   =    "F:\焦点切换\页签小图2\页签小图2\sc_1.gif "; 
 var   img_b   =   new   Image(); 
 img_b.src   =    "F:\焦点切换\页签小图2\页签小图2\sc_2.gif "; 
 var   img_c   =   new   Image(); 
 img_c.src   =    "F:\焦点切换\页签小图2\页签小图2\zt_1.gif "; 
 var   img_d   =   new   Image(); 
 img_d.src   =    "F:\焦点切换\页签小图2\页签小图2\zt_2.gif ";   
 function   MM_swapImgRestore()    
 {    
 var   i,x,a=document.MM_sr;    
 for(i=0;a&&i <a.length&&(x=a[i])&&x.oSrc;i++)    
 x.src=x.oSrc; 
 }   
 function   MM_preloadImages()    
 {    
 var   d=document;    
 if(d.images) 
 {    
 if(!d.MM_p)   d.MM_p=new   Array(); 
 var   i,j=d.MM_p.length,a=MM_preloadImages.arguments;    
 for(i=0;   i <a.length;   i++) 
 if   (a[i].indexOf( "# ")!=0) 
 {    
 d.MM_p[j]=new   Image;    
 d.MM_p[j++].src=a[i]; 
 } 
 } 
 }   
 function   MM_findObj(n,   d)    
 {    
 var   p,i,x;       
 if(!d)   d=document;    
 if((p=n.indexOf( "? "))> 0&&parent.frames.length)    
 { 
 d=parent.frames[n.substring(p+1)].document;    
 n=n.substring(0,p); 
 } 
 if(!(x=d[n])&&d.all)   x=d.all[n];    
 for   (i=0;!x&&i <d.forms.length;i++)   x=d.forms[i][n]; 
 for(i=0;!x&&d.layers&&i <d.layers.length;i++)   x=MM_findObj(n,d.layers[i].document); 
 if(!x   &&   d.getElementById)   x=d.getElementById(n);    
 				return   x; 
 }   
 function   MM_swapImage()    
 { &