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

The above each output is: one,two,three,four

var arr = [ "aaa", "bbb", "ccc" ];
$.each(arr, function(i,a){
alert(i); // i  Is the ordinal number of the loop
alert(a); // a  Is the value
});
var arr1 = [[1, 4, 3], [4, 6, 6], [7, 20, 9]]
$.each(arr1, function(i, item){
alert(item[0]);
});

In fact, arr1 is a 2-dimensional array, and item is equivalent to taking every 1-dimensional array, item[0] takes the first value in every 1-dimensional array So the each output above is: 1, 4, 7

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

The output result is: 1, 2, 3, 4

This is the end of this article, I hope you enjoy it.