发布于 2017-02-18 23:23:22 | 166 次阅读 | 评论: 0 | 来源: 网友投递

这里有新鲜出炉的Javascript教程,程序狗速度看过来!

JavaScript客户端脚本语言

Javascript 是一种由Netscape的LiveScript发展而来的原型化继承的基于对象的动态类型的区分大小写的客户端脚本语言,主要目的是为了解决服务器端语言,比如Perl,遗留的速度问题,为客户提供更流畅的浏览效果。


这篇文章主要介绍了JavaScript中循环遍历Array与Map的各种方法,利用的都是js入门学习中的基础知识,需要的朋友可以参考下

js循环数组各种方法
eg1:


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


eg2:


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]);} 

eg3:


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


eg4:


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


eg5:


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


eg6:


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


eg7:


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 loop 
var items = ['one','two','three'], i=items.length; 
while(i--){ 
 console.log(items[i]); 
} 
 
// logs: 'three','two','one' 
 
or the classical for loop 
var items = ['one','two','three'] 
for(var i=0,l=items.length; i < l ; i++){ 
 console.log(items[i]); 
} 
 
// logs: 'one','two','three' 


eg8:


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 
} 

js循环map,获取所有的key和value
eg1:


//Page地址 
 pageUrl : { 
  menu   : "loadPage.htm?url=/collect/menu.page",   // 进入菜单页面 
  guangfaPage  : "loadPage.htm?url=/collect/menu.page",   // 进入广发信息收集页面 
  pinganPage  : "loadPage.htm?url=/collect/menu.page",   // 进入平安信息收集页面 
  nuonuoPage  : "loadPage.htm?url=/collect/menu.page",   // 进入诺诺信息收集页面 
  youbangPage  : "loadPage.htm?url=/collect/menu.page",   // 进入友邦信息收集页面 
  inputMobileNo : "loadPage.htm?url=/collect/inputMobileNo.page", // 进入输入手机号页面 
  readIdCard  : "loadPage.htm?url=/collect/readIdCard.page",  // 进入读取身份证页面 
  member   : "loadPage.htm?url=/collect/member.page",   // 进入输入会员卡号页面 
  bankCard  : "loadPage.htm?url=/collect/bankCard.page",   // 进入插入银行卡页面 
  url   : "loadPage.htm?url=/collect/url.page"    // 进入跳转url页面 
 }, 
 
for(var key in this.pageUrl){ 
 alert(key+" : "+this.pageUrl[key]); 
} 


eg2:


var obj = { 
 "a": 1, 
 "b": 2, 
 "c": 3 
}; 
 
for (var prop in obj) { 
 if (obj.hasOwnProperty(prop)) { 
 // or if (Object.prototype.hasOwnProperty.call(obj,prop)) for safety... 
 alert("prop: " + prop + " value: " + obj[prop]) 
 } 
} 


双重Map循环
eg:


var msg = ""; 
for(var key in Pin) { 
 for(var i in Pin[key]){ 
 msg+=i+": "+Pin[key][i]+"\n"; 
 } 
} 
alert(msg); 



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