Basic knowledge of JavaScript variables_Basic knowledge

1.区分大小写

2.弱类型变量

    全部的变量都用var关键字标示，JavaScript解释器会自动分配

3.句子的尾部分号是可选的

    如：var name=23; or var name=23都可以

4.代码可以嵌入在html中也可以引入js文件

   

4.1 code can be imported directly from another file

For example: The result is the same

5. Multiple variables can be declared at the same time

For example: var name="JerryZhang",age=23,sex="male";

document.write(name "
" sex "
" age);

6.can not be initialized

such as : var name;

document.write(name);

7 Variable definitions cannot use keywords or reserved words (note: I don’t know what reserved words are)

For example: html, title, history are all OK, but document is not;

Such as : var html="asp.net";

document.write(html);

8. Variables in JavaScript can store multiple types of variables

For example: var i=23;

document.write(i "
");

i="JerryZhang";

document.write(i "
");