JavaScript 数据类型
字符串（String）、数字(Number)、布尔(Boolean)、数组(Array)、对象(Object)、空（Null）、未定义（Undefined）。
<!DOCTYPE html>
<html><body><script>
var person={ firstname : "John",lastname : "Doe",id : 5566};document.write(person.lastname + "<br>");document.write(person["lastname"] + "<br>");</script></body>
</html><script>
var i;var cars = new Array();cars[0] = "Saab";cars[1] = "Volvo";cars[2] = "BMW";for (i=0;i<cars.length;i++)
{ document.write(cars[i] + "<br>");}</script>
var carname=new String; var x= new Number; var y= new Boolean; var cars= new Array; var person= new Object;