//01-变量、常量的定义 let mydata ; mydata="hello world!"; //变量名区分大小写 let mystring ="long long ago ,there was a king" let Mystring="ha ha" //字符串用单引号也行 let myname='my name is 张三' console.log(mydata); console.log(mystring); console.log(myname) //定义常量 const MYCONSTVALUE=100;
//02-JavaScript基本数据类型 //字符串(String) let mystring='Some Text'; let anotherString='Some More Text' console.log(anotherString) //数值(Number) let myInteger=10; let cost=1.33; console.log(myInteger) console.log(cost) //布尔 let yes=true; let no=false; console.log(yes) console.log(no) //数组 let arr1=[1,3,5,7,9] let arr2=["one","two","three"]; let first=arr2[0]; console.log(arr1); console.log(arr2); console.log(first); //对象 object Literal let person={"name":"Tom","age":11,"address":"北京市朝阳区"} console.log(person); console.log(person.address); //Null 空,变量中没有任何值来存储 let newvar=null; console.log(newvar) //JavaScript 是一种无类型语言,脚本中不需要指定变量的数据类型,解释器自动判断。 //此外可以将不同类型的值付给一种类型的变量。 let id="testId"; id=1; console.log(id);