标签：return reject div http time back body head color
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>练习</title> </head> <style> .light{ width:200px; height: 200px; border-radius:50%; background:red; } .light2{ width:200px; height: 200px; border-radius:50%; background:red; } </style> <body> <div class="light"></div> <div class="light2"></div> <script> //promise实现 红绿灯 var light=document.getElementsByClassName("light")[0]; var r=function(){ return new Promise(function(resolve,reject){ light.style.background="red"; setTimeout(resolve,3000); }) }; var y=function(){ return new Promise(function(resolve,reject){ light.style.background="yellow"; setTimeout(resolve,2000); }) } var g=function(){ return new Promise(function(resolve,reject){ light.style.background="green"; setTimeout(resolve,4000); }) } var xun=function(){ r().then(function(){ return y(); }).then(function(){ return g(); }).then(function(){ return xun(); }); } xun(); //async/await实现红绿灯 const lignt2=document.getElementsByClassName("light2")[0]; function changeLightColor(color,duration){ return new Promise(function(resolve,reject){ lignt2.style.background=color; setTimeout(resolve,duration); }) } async function xun2 (){ await changeLightColor("red",3000); await changeLightColor("yellow",2000); await changeLightColor("green",4000); xun2(); } xun2();//执行 </script> </body> </html>
标签：return reject div http time back body head color
原文地址：https://www.cnblogs.com/fqh123/p/10421696.html
