var i=0;  
var adl=new Array(2,2,2); 
//6是设置的时间 
var timer=setInterval("run()",adl[i]*1000); 
function run() 
{ 
    for(j=0;j<adl.length;j++) 
    { 
        var x=document.getElementById("srh"+j); 
        if(j==i) x.style.display="block"; 
        else x.style.display="none"; 
    } 
clearInterval(timer); 
timer=setInterval("run()",adl[i]*1000); 
i=(i<adl.length-1)?++i:0; 
}