// JavaScript Document  
function changechannel(n)
   {
    for(i=1;i<3;i++)
    {
     eval("document.getElementById('channel"+i+"').className='case2'");
    }
    eval("document.getElementById('channel"+n+"').className='cover'");
    
    for(i=1;i<3;i++)
    {
      eval("document.getElementById('layer"+i+"').style.display='none'")
    }
      eval("document.getElementById('layer"+n+"').style.display='block'");
   }
   
   function changechannel1(n)
   {
   	for(i=1;i<3;i++)
    {
     eval("document.getElementById('channel"+i+"').className='case1'");
    }
    eval("document.getElementById('channel"+n+"').className='cover1'");
    
    for(i=1;i<3;i++)
    {
      eval("document.getElementById('layer"+i+"').style.display='none'")
    }
      eval("document.getElementById('layer"+n+"').style.display='block'");	
   }