// --- 获取ClassName 
document.getElementsByClassName = function(cl) { 
var retnode = []; 
var myclass = new RegExp('\\b'+cl+'\\b'); 
var elem = this.getElementsByTagName('*'); 
for (var j = 0; j < elem.length; j++) { 
var classes = elem[j].className; 
if (myclass.test(classes)) retnode.push(elem[j]); 
} 
return retnode; 
} 
// --- 隐藏所有 
function HideAll() { 
var items = document.getElementsByClassName("optiton"); 
for (var j=0; j<items.length; j++) { 
items[j].style.display = "none"; 
} 
} 
window.onload = function() { 
var show_item = "opt_1"; 
document.getElementById(show_item).style.display = "block"; 
var items = document.getElementsByClassName("title"); 
for (var j=0; j<items.length; j++) { 
items[j].onmouseover = function() { 
var o = document.getElementById("opt_" + this.name); 
if (o.style.display != "block") { 
HideAll(); 
o.style.display = "block"; 
} 
else { 
o.style.display = "none"; 
} 
} 
} 

var focus = new Focus(imgs,'focus_m');    //这句是photo.js中的代码，如果不要中间图片效果，这句可以删去
}