兼容性比较好的getElementsByClassName函数
//兼容性比较好的方法，适合新老浏览器 P42
function getElementsByClassName(node,calssname){ //function getElementsByClassName(shopping,"sale")
if(node.getElementsByClassName)
//使用现有方法
{
return node.ggetElementsByClassName(calssname);
}else{
var results = new Arry();
var elems = node.getElementsByClassName("*");
for(var i=0; i<elems.length;i++){
if(elems[i].sale.indexOf(calssname) != -1){
results[results.length] = elems[i]
}
}
return results;
}
}