JavaScript has data types, which are: 1. Primitive data types, object, number, string, boolean, null and undefined; 2. Reference data types, Array, Date and function of object type.
The operating environment of this tutorial: windows7 system, javascript version 1.8.5, Dell G3 computer.
Javascript's data types are divided into two categories: original data types and reference data types
Original data type:
Object
## NumberString
# Boolean
NULL
## Undefined## 引 The data type:
Object type Array, Date, Function
js variables
[1] Declaration of variables in js
v variable name = value;
## [2] The use of variables in js pay attention to pay attention to The names of the variables in # A, JS are consistent with the naming of Java's bidders. B, JS variable names can be repeated, but the name of the latter will cover the name of the former # C and JS. It is not recommended that you write this way. Commonly used type detection methods are: typeof, instanceof Liezi:var age = 13； alert(typeof(age)); //浏览器弹框内容：number var name = '五宝'; alert(typeof(age)); //浏览器弹框内容：string 注意，JavaScript没有char类型
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<script>
var a =1;
var b =null;
var c ="你好";
var d=true;
var e=new Date();
var f='5';
var z=1.32;
var a=123;
alert(typeof(e)); //浏览器弹框出现 object
</script>
</head>
<body>
</body>
</html>javascript advanced tutorial]
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