[2015-12-10简介]每天看一点[JavaScript.DOM编程艺术（第2版）]

13:23~14:30 第2章

-------------------------------------------------------------------------------------------

1.数据类型

　变量名:　字母 数字 $ _  (第一个不允许是数字)

　　　　　 下划线分隔每个单词

　函数名:　驼峰格式命名 myMode

-------------------------------------------------------------------------------------------

2.声明变量,不需要进行类型声明:弱类型

var a = 'don\'t ask'

var a = "don't ask"

var a = -3.22222(任意位小数)

-------------------------------------------------------------------------------------------

3.数组

var aa = Array(4);

var aa = Array();

aa[0] = "john";

var aa = Array( "rr", 33, true);

var aa = [ "rr", 33, true];

var aa =Array();

var bb = [];

-------------------------------------------------------------------------------------------

4.对象

var lennon = Object(); 

lennon.name = "john";

var lennon = { na me:"John", year:1940, living:false };

-------------------------------------------------------------------------------------------

5.比较

var a =false;
var b = "";
if(a === b){
alert("a is b");
}else{
alert("a isnot b");
}

== 比较值

=== 比较值和类型

!= 比较值

!== 比较值和类型

逻辑 && || !

-------------------------------------------------------------------------------------------

6.循环

var count = 1;
while(count <=11){
alert(count);
count++;
}

do{
alert(count);
count++;
}while(count<11);

for(var count =1;count<11;count++){
alert(count);
}

var aa = [ "ruj", 33, false];
for(var count =0;count<aa.length;count++){
alert(count);
}

-------------------------------------------------------------------------------------------

7.函数

函数里    有var ----局部变量

　　　　无var ----全局变量

 -------------------------------------------------------------------------------------------

var jeremy = new Person; //jeremy具备了Person的属性和方法

内建对象:Array Date Math等等

var current_date = new Date();

var today = current_date.getDay();

宿主对象:由浏览器提供的预定义对象:document form element等

转载于:https://www.cnblogs.com/rysly/p/js-2.html