js循环数组各种步骤array-升级版

js循环数组各种方法array-升级版

var myStringArray = ["Hello","World"];for (var i = 0; i < myStringArray.length; i++) {    alert(myStringArray[i]);    //Do something}

Array.prototype.foo = "foo!";var array = ['a', 'b', 'c'];for (var i in array) {  alert(array[i]);}for(var i in this.$GLOBAL_DETAIL.album_photo_ids){if(this.$GLOBAL_DETAIL.album_photo_ids[i] == "3487675024077108") alert(this.$GLOBAL_DETAIL.album_photo_ids[i]);}

[1,2,3,4].map( function(item) {     alert(item);})

var x = [1,2,3,4].map( function(item) { return item * 10; } );// And now x is [10,20,30,40]

var myStringArray = [ "Hello", "World" ]var len = myStringArray.lengthfor (var i=0; i<len; ++i) {  if (i in myStringArray) {    var s = myStringArray[i];    ... do something with s ...  }}

var myStringArray = [ "Hello", "World" ]myStringArray.forEach( function(s) {      ... do something with s ...} )

var i=0,item,items = ['one','two','three'];while(item=items[i++]){    console.log(item);}// logs: 'one','two','three'and for the reverse order, an even more efficient loopvar items = ['one','two','three'], i=items.length;while(i--){    console.log(items[i]);}// logs: 'three','two','one'or the classical for loopvar items = ['one','two','three']for(var i=0,l=items.length; i < l ; i++){    console.log(items[i]);}// logs: 'one','two','three'

var myStringArray = ['Hello', 'World']; // array uses [] not {}for (var i in myStringArray) {    console.log(i + ' -> ' + myStringArray[i]); // i is the index/key, not the item}