<html><head lang="en">
<meta charset="UTF-8">
<title></title>
<script>
var age = ; //number
var money = 100.09;//number
var score = -;//number
// 尽量不要使用双引号
var name = "jack";//string
var name2 = 'rose';//string
var result = true; // false; boolean
var name3 = null; // 赋空值 object
// console.log(age, money, score, name, name2, result, name3);
// console.log(typeof age,typeof money,typeof score,typeof name,typeof name2,typeof result,typeof name3);
var newName = name +'-' + name2 + age;
// console.log(newName);
// 运算是从左往右, 任何类型和string类型相拼接都会变成string类型
var str1 = + + '' + ''; //
var str2 = '' + + + ''; //
var str3 = ( + ) + '' + '';//
var str4 = '' + '' + + ; // 10101010
// console.log(str4);
// 数组
var arr = [age, money, '殷婷婷', name, result, name3, , ['哈哈', ]];
// 数组的长度
// console.log(arr.length);
// 遍历数组
// for(var i =0; i<arr.length; i++){
// console.log(arr[i]);
// }
// console.log(arr[7][1]);
console.log(typeof arr); //object
</script>
</head>
<body>
<!--<button onclick="alert("你好");">百度一下</button>-->
</body></html>