在H5场景动画时，常常会用到着一样一个效果，箭头持续上下跳动来引导用户上下滑动整个页面
<!DOCTYPE html > <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>css动画--元素上下跳动</title> <style type="text/css"> @-webkit-keyframes bounce-down { 25% {-webkit-transform: translateY(-10px);} 50%, 100% {-webkit-transform: translateY(0);} 75% {-webkit-transform: translateY(10px);} } @keyframes bounce-down { 25% {transform: translateY(-10px);} 50%, 100% {transform: translateY(0);} 75% {transform: translateY(10px);} } .animate-bounce-down{ background:#333; width: 100px; height: 100px; margin:100px auto;-webkit-animation: bounce-down 1.5s linear infinite;animation: bounce-down 1.5s linear infinite; } @-webkit-keyframes bounce-up { 25% {-webkit-transform: translateY(10px);} 50%, 100% {-webkit-transform: translateY(0);} 75% {-webkit-transform: translateY(-10px);} } @keyframes bounce-up { 25% {transform: translateY(10px);} 50%, 100% {transform: translateY(0);} 75% {transform: translateY(-10px);} } .animate-bounce-up{ background:#ddd; width: 100px; height: 100px; margin:100px auto;-webkit-animation: bounce-up 1.4s linear infinite;animation: bounce-up 1.4s linear infinite;} </style> </head> <body> <div class="animate-bounce-up"></div> <div class="animate-bounce-down"></div> </body> </html>