<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>案例1</title> </head> <body> <img id="light" src="imgs/off.gif"> <br> <script> //定时器 // 获取img元素 // 标识 数字 let number = 0; setInterval(function (){ //获取元素 let img = document.getElementById("light"); //判断 if ( number % 2 == 0 ){ img.src = "imgs/off.gif"; }else{ img.src = "imgs/on.gif"; } //标识改变 number++; },1000) </script> </body> </html>
