1.基本语法(常量,属性定义)
<script text="text/javascript"> //1.基本语法 var age = 18; //number var money = 10.88; //number var name = 'Steven'; //string var family_name = "Rose"; //string var result = true;//false //boolean var number = null;//为空 //object var number2 = undefined;//未定义 //undefined </script>
2.如何进行输出(类型)
<script text="text/javascript"> //2.如何进行输出 console.log(age,money,name,family_name,result,number,number2); //3.变量的真实类型 typeof console.log(typeof age,typeof money,typeof name,typeof family_name,typeof result,typeof number,typeof number2); //number number string string boolean object undefined </script>
3.基本数据类型的运算
<script text="text/javascript"> //4.基本数据类型的运算 //遵循的规律:运算是从左往右; 任何类型的变量与string类型的变量拼接都会被强转为字符串 //4.1 字符串的拼接 var newName = name + '&' + family_name; console.log("newName:" + newName); //4.2 题目 var str1 = 10 + 10 + '10'; //2010 var str2 = '10' + 10 + 10; //101010 var str3 = (10 + '10') + 10;//101010 console.log("str1:" + str1); console.log("str2:" + str2); console.log("str3:" + str3); </script>
4.数组及使用
<script text="text/javascript"> //5.数组:可以装任意类型 var numbers =[-10,'san',name,result,number,['a','b']]; console.log(numbers) //5.1 遍历数组 for (var i = 0; i<numbers.length ; i++){ console.log('elementA:'+numbers[i]); } //5.2 JS中常用属性 // 删除数组中最后一个内容 numbers.pop();//出栈 // 插入一个内容 numbers.push('XMG'); for (var i in numbers){ console.log(i,numbers[i]); } //6.JS 常用的类库 Math var numsArr = [10,212,3223,32]; //取最大值 var maxNum = Math.max(210,21,10); //Math.max(numsArr); //不识别 Nan var newMax = Math.max.apply(this,numsArr); console.log(maxNum); console.log(newMax); </script>