初学JavaScript须知道的七件事

Posted 2020-08-14

1.1、缩略标记

//定义对象           
           //var car = new Object();
            //car.colour = ‘red‘;
            //car.wheels = 4;
            //car.hubcaps = ‘spinning‘;
            //car.age = 4;
            
            //上述代码的简洁写法：
            var car = {
                colour: ‘red‘,
                wheels: 4,
                hubcaps: ‘spinning‘,
                age: 4
            }
//定义数组
            var testArr = new Array(‘str1‘, ‘str2‘, ‘str3‘, ‘str4‘);
            //上述代码的简洁写法：
            var testArr = [‘str1‘, ‘str2‘, ‘str3‘, ‘str4‘];   
//关联数组
            var car = new Array();
            car[‘colour‘] = ‘red‘;
            car[‘wheels‘] = 4;
            car[‘hubcaps‘] = ‘spinning‘;
            car[‘age‘] = 4;     
//三重标记法
　　　　　　var direction;
　　　　　　if(x<200){ direction=1;}else{direction=-1}
　　　　　　//用三重标记法可写为
　　　　　　var direction=x<200?1:-1;

1.2、JSON数据格式

JSON是javascript Object Notion的缩写

       //描述乐队 
       var band = {
                "name": "The Red Hot Chili Peppers",
                "members": [
                    {
                        "name": "zhangsan",
                        "role": "lead vocals"
                    }, {
                        "name": "lisi",
                        "role": "bass guitar,trumpet,backing vocals"
                    }
                ],
                "year":"2009"
            }

　　JSON-P 跨域应用：http://www.cnblogs.com/chopper/archive/2012/03/24/2403945.html