lovecoding
/
Web1020


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./js/vue.js"></script>
</head>
<body>
    <div id="app">
        <h1>{{num1}}+{{num2}}={{sum}}</h1>
        <button @click="changeFun">change</button>
    </div>
    <script>
        var app = new Vue({
            el: '#app',
            data:{
                num1:1,
                num2:2,
                sum:0,
                arr:[1,2,3],
                obj:{
                    a:1,
                    b:{
                        c:1
                    }
                }
            },
            methods:{
                changeFun:function(){
                    this.num2 = 100;
                    this.num1 = 100;
                    this.arr[1] = 100;
                    // this.arr = ['a','b','c']
                    this.obj.b = 100;
                }
            },
            watch:{
                num2:function(val,oldVal){
                    // watch 监听num2的变化 接受两个参数 val 代表新值 oldVal 代表旧值
                    console.log("num2=",val,oldVal)
                    this.sum = this.num1 + val
                },
                num1:{
                    handler(val,oldVal){
                        console.log("num1=",val,oldVal)
                    }
                },
                arr:{
                    handler(val,oldVal){
                        console.log("arr=",val,oldVal)
                    },
                    deep:true
                },
                obj:{
                    handler(val,oldVal){
                        console.log("obj=",val,oldVal)
                    },
                    deep:true
                }
            }
        })
        

    </script>
</body>
</html>