一，效果图。
二，代码。
<!DOCTYPE html>
<html> <head> <meta charset="utf-8"> <title>javascript 数据类型</title> </head> <body> <script type="text/javascript"> var carname1 = "volvo xc60"; var carname2 = "volvo xc60"; var answer1 = "it's alrght"; var answer2 = "he is called johnny"; var answer3 = "he is called johnny"; document.write(carname1 + "<br>"); document.write(carname2 + "<br>"); document.write(answer1 + "<br>"); document.write(answer2 + "<br>"); document.write(answer3 + "<br>"); </script> <script type="text/javascript"> var x1 = 34.00; var x2 = 34; var y = 123e5; var z = 123e5; document.write(x1 + "<br>"); document.write(x2 + "<br>"); document.write(y + "<br>"); document.write(z = "<br>"); </script> <script type="text/javascript"> var i; var cars = new Array(); cars[0] = "saab"; cars[1] = "volvo"; cars[2] = "bmw"; for (var i = 0; i < cars.length; i++) { document.write(cars[i] + "<br>"); }; </script> <script> var person = { firstname: "John", lastname: "Doe", id: 5566 }; document.write(person.lastname + "<br>"); document.write(person["lastname"] + "<br>"); </script> <script> var person; var car = "Volvo"; document.write(person + "<br>"); document.write(car + "<br>"); var car = null document.write(car + "<br>"); </script> </body> </html>
参考资料：《菜鸟教程》
一，效果图。
二，代码。
<!DOCTYPE html>
<html> <head> <meta charset="utf-8"> <title>javascript 数据类型</title> </head> <body> <script type="text/javascript"> var carname1 = "volvo xc60"; var carname2 = "volvo xc60"; var answer1 = "it's alrght"; var answer2 = "he is called johnny"; var answer3 = "he is called johnny"; document.write(carname1 + "<br>"); document.write(carname2 + "<br>"); document.write(answer1 + "<br>"); document.write(answer2 + "<br>"); document.write(answer3 + "<br>"); </script> <script type="text/javascript"> var x1 = 34.00; var x2 = 34; var y = 123e5; var z = 123e5; document.write(x1 + "<br>"); document.write(x2 + "<br>"); document.write(y + "<br>"); document.write(z = "<br>"); </script> <script type="text/javascript"> var i; var cars = new Array(); cars[0] = "saab"; cars[1] = "volvo"; cars[2] = "bmw"; for (var i = 0; i < cars.length; i++) { document.write(cars[i] + "<br>"); }; </script> <script> var person = { firstname: "John", lastname: "Doe", id: 5566 }; document.write(person.lastname + "<br>"); document.write(person["lastname"] + "<br>"); </script> <script> var person; var car = "Volvo"; document.write(person + "<br>"); document.write(car + "<br>"); var car = null document.write(car + "<br>"); </script> </body> </html>
参考资料：《菜鸟教程》