监听属性可以针对某个属性进行监听，当监听的属性的值发生了变化，则会执行相应的函数。
监听的函数要写在vue的watch属性中。
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <script src="https://cdn.jsdelivr.net/npm/vue"></script> <title>vue中监听属性</title> </head> <body> <div id="app"> <div> <label>查询：</label> <input type="text" v-model:value="keyword"> </div> <span>结果：{{ret}}</span> </div> <script> new Vue({ el: "#app", data: { keyword: '', ret: '', }, watch: { keyword(searchWord, retWord) { this.ret = '正在加载...' setTimeout(()=>{ this.ret = searchWord },1000); } } }) </script> </body> </html>