老师,多次点击‘开始按钮’使定时器叠加,点‘暂停按钮’很多次怎么也清除不了,这是什么原因
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | <!DOCTYPE html> < html lang = "en" > < head > < meta charset = "UTF-8" > < meta http-equiv = "X-UA-Compatible" content = "IE=edge" > < meta name = "viewport" content = "width=device-width, initial-scale=1.0" > < title >Document</ title > </ head > < body > < h1 id = "info" >0</ h1 > < button id = "btn1" >开始</ button > < button id = "btn2" >暂停</ button > < script > var oInfo = document.getElementById('info'); var oBtn1 = document.getElementById('btn1'); var oBtn2 = document.getElementById('btn2'); var a = 0; //全局变量 var timer; oBtn1.onclick = function () { //为了防止定时器叠加,我们应该在设置定时器之前清除定时器 // clearInterval(timer); //更改全局变量timer的值为一个定时器实体 timer = setInterval(function () { oInfo.innerText = ++a; },1000) }; oBtn2.onclick = function () { clearInterval(timer); }; </ script > |
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