1 <html lang="en"> 2 <head> 3 <meta charset="UTF-8"> 4 <meta name="viewport" content="width=device-width, initial-scale=1.0"> 5 <meta http-equiv="X-UA-Compatible" content="ie=edge"> 6 <title>定时器累加</title> 7 <style> 8 .box{ 9 width: 100px; 10 height: 100px; 11 background-color: red; 12 } 13 </style> 14 </head> 15 <body> 16 <div class="box"></div> 17 <script> 18 window.onload=function(){ 19 var box = document.getElementsByClassName("box")[0] 20 var height=0,timer=null; 21 box.onmouseover=function(){ 22 clearInterval(timer); //清除定时器 23 24 timer=setInterval(function(){ 25 height+=1; 26 console.log(height) 27 },1000) 28 } 29 } 30 31 </script> 32 </body> 33 </html>