function welcomedefaultqiehuan(divid,i)
{
    var n1=document.getElementById("d1");
    var n2=document.getElementById("d2");
    var n3=document.getElementById("d3");
    
    n1.style.display="none";
    n2.style.display="none";
    n3.style.display="none";
    var divid=document.getElementById(divid);
    divid.style.display = "block";
    
    var img_d1=document.getElementById("img_1");
    var img_d2=document.getElementById("img_2");
    var img_d3=document.getElementById("img_3");
    img_d1.src = "images/item1.jpg";
    img_d2.src = "images/item2.jpg";
    img_d3.src = "images/item3.jpg";
    
    var img = document.getElementById("img_"+i);
    img.src = 'images/item'+i+'_over.jpg';
    
}