jQuery中$.each的用法

var arr1 = [ "one", "two", "three", "four", "five" ];
$.each(arr1, function(){
    alert(this);
});
输出：one   two  three  four   five
var arr2 = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
$.each(arr2, function(i, item){
    alert(item[0]);
});
输出：1   4   7
var obj = { one:1, two:2, three:3, four:4, five:5 };
$.each(obj, function(key, val) {
    alert(obj[key]);     
});
输出：1   2  3  4  5