<!DOCTYPE html>
<html>
<head> 
<meta charset="utf-8"> 
<title>菜鸟教程(runoob.com)</title> 
</head>
<body>

<script>
var carname1="Volvo XC60";
var carname2='Volvo XC60';
var answer1='It\'s alright';
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>

</body>
</html>

<!DOCTYPE html>
<html>
<head> 
<meta charset="utf-8"> 
<title>菜鸟教程(runoob.com)</title> 
</head>
<body>

<script>
var x1=34.00;
var x2=34;
var y=123e5;
var z=123e-5;
document.write(x1 + "<br>")
document.write(x2 + "<br>")
document.write(y + "<br>")
document.write(z + "<br>")
</script>

</body>
</html>

<!DOCTYPE html>
<html>
<body>

<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>

</body>
</html>

<!DOCTYPE html>
<html>
<head> 
<meta charset="utf-8"> 
<title>菜鸟教程(runoob.com)</title> 
</head>
<body>

<script>
var person=
{
    firstname : "John",
    lastname  : "Doe",
    id        :  5566
};
document.write(person.lastname + "<br>");
document.write(person["lastname"] + "<br>");
</script>

</body>
</html>

<!DOCTYPE html>
<html>
<head> 
<meta charset="utf-8"> 
<title>菜鸟教程(runoob.com)</title> 
</head>
<body>

<script>
var person;
var car="Volvo";
document.write(person + "<br>");
document.write(car + "<br>");
var car=null
document.write(car + "<br>");
</script>

</body>
</html>