【指教】javascript实现点击图片互斥
目前我需要做5个图片,当然。这个五个图片默认是a.gif   
 当点击其中一个时,图片换为b.gif,再点击此图片时换为a.gif; 
 其实就是这几个图片是互斥的关系。我做了一个。不过。不好用。 
 希望那位大侠帮忙一下     
  <!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> 无标题文档 </title>  
  </head>    
  <body>  
  <script>  
 function   changeImg(obj,n) 
 {   
 	for(i=0;i <document.all.img.length;i++) 
 	{     
 		if(obj.checked) 
 		{   
 		document.all.img[i].src= "a.gif ";  		 
 		document.getElementsByName( "img ")[n-1].src= "b.gif ";   
 		} 
 		else 
 		{   
 		}   
 	}   
 } 
  </script>    
  <table   width= "200 "   border= "1 ">  
        <tr>  
              <td   onClick= "changeImg(this,1); ">  <img   src= "a.gif "   name= "img "   value= "img "   id=1/>  </td>  
              <td   onClick= "changeImg(this,2); ">  <img   src= "a.gif "   name= "img "   value= "img "   id=2/>  </td>  
              <td   onClick= "changeImg(this,3); ">  <img   src= "a.gif "   name= "img "   value= "img "   id=3/>  </td>  
              <td   onClick= "changeImg(this,4); ">  <img   src= "a.gif "   name= "img "   value= "img "   id=4/>  </td>  
              <td   onClick= "changeImg(this,5); ">  <img   src= "a.gif "   name= "img "   value= "img "   id=5/>  </td>  
        </tr>  
  </table>  
  </body>  
  </html>    
------解决方案--------------------如果是多行~~   
  <html>  
  <script>  
 var pic1= "a.gif "; 
 var pic2= "b.gif "; 
 function changeImg(obj){ 
     var tr=obj.parentNode; 
     if(tr.focusImg)tr.focusImg.src=pic1; 
     var img=obj.getElementsByTagName( "img ")[0]; 
     img.src=pic2; 
     tr.focusImg=img; 
 } 
  </script>  
  <body>  
  <table width= "200 " border= "1 ">  
    <tr>  
      <td onClick= "changeImg(this) ">  <img src= "a.gif " />  </td>  
      <td onClick= "changeImg(this) ">  <img src= "a.gif " />  </td>  
      <td onClick= "changeImg(this) ">  <img src= "a.gif " />  </td>  
      <td onClick= "changeImg(this) ">  <img src= "a.gif " />  </td>  
      <td onClick= "changeImg(this) ">  <img src= "a.gif " />  </td>  
    </tr>  
    <tr>  
      <td onClick= "changeImg(this) ">  <img src= "a.gif " />  </td>  
      <td onClick= "changeImg(this) ">  <img src= &qu