jqueryの$().eachと$.eachの違いは何ですか?

{
if($(this).attr(‘checked’)==true)
{
//一些操作代码
}
回调函数是可以传递参数，i就为遍历的索引。

$.each([{name:"limeng",email:"xfjylimeng"},{name:"hehe",email:"xfjylimeng"}],function(i,n)
{
alert("索引:"+i+"对应值为："+n.name);
});

var arr1 = [ "one", "two", "three", "four", "five" ];
$.each(arr1, function(){
alert(this);
});

var arr2 = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
$.each(arr2, function(i, item){
alert(item[0]);
});

var obj = { one:1, two:2, three:3, four:4, five:5 };
$.each(obj, function(key, val) {
alert(obj[key]);
});