css3怎么设置网页背景（用css3实现惊艳面试官的背景即背景动画）

我们传统的前端更多的是用javascript实现各种复杂动画，自从有了Css3 transition和animation以来,前端开发在动画这一块有了更高的自由度和格局,对动画的开发也越来越容易。这篇文章就让我们汇总一下使用Css3实现的各种特效。这篇文章参考《css揭秘》这本书，并作出了自己的总结，希望能让大家更有收获，也强烈推荐大家看看这本书，你值得拥有。

我们将学到

• Css3
• outline
• radial-gradient
• linear-gradient
• box-shadow

1.实现内部虚线边框

知识点：outline

核心代码.dash-border{ width: 200px; height: 100px; line-height: 100px; outline: 1px dashed #fff; outline-offset: -10px; } 复制代码

2.边框内圆角的实现

知识点：box-shadow

核心代码.radius-border{ margin-top: 20px; width: 180px; height: 80px; box-shadow: 0 0 0 10px gray; } 复制代码

3.实现条纹背景与进度条

知识点：linear-gradient,repeating-linear-gradient

核心代码/* 上 */ background: linear-gradient(to right,#fb3 50%,#58a 0); background-size: 40px 100%; box-shadow: inset 0 0 3px #555; /* 中 */ background: linear-gradient(45deg,#fb3 25%,#58a 0,#58a 50%,#fb3 0,#fb3 75%,#58a 0); background-size: 40px 40px; /* 下 (可以实现任意角度的渐变，45°时显示效果最好) */ background: repeating-linear-gradient(60deg,#fb3,#fb3 15px,#58a 0,#58a 30px); 复制代码

4.复杂的背景图案

知识点：linear-gradient,repeating-linear-gradient,radial-gradient

由于第二个图会有复杂的随机动画，建议大家可以亲自尝试看看效果，核心代码

<style> .bg-grid{ margin-top: 20px; width: 200px; height: 200px; background-image: linear-gradient(rgba(255,255,255,1) 2px,transparent 0), linear-gradient(to right,rgba(255,255,255,1) 2px,transparent 0), linear-gradient(rgba(255,255,255,.2) 1px,transparent 0), linear-gradient(to right,rgba(255,255,255,.2) 1px,transparent 0); background-position: -50px -50px; background-size: 100px 100px,100px 100px, 100% 10px, 10px 100%; } .animate-grid{ animation: move-grid 6s linear infinite; } @keyframes move-grid{ 0%{ background-position: -50px -50px; } 30%{ background-position: -100px -100px; } 60%{ background-position: -100px -150px; } 100%{ background-position: -50px -50px; } } </style> <div class="bg-grid black-theme"></div> <div class="bg-grid black-theme animate-grid"></div> 复制代码

红绿灯以及红路灯随机运动动画

利用css3多背景和position实现红绿灯和背景色块移动核心代码

<style> .bg-dot{ margin-top: 20px; width: 200px; height: 50px; background-image: radial-gradient(circle,#0cf 15px,transparent), radial-gradient(circle,red 15px,transparent), radial-gradient(circle,yellow 15px,transparent), radial-gradient(circle,green 15px,transparent); background-repeat: no-repeat; background-position: 0 0, 50px 0, 100px 0, 150px 0, 200px 0; background-size: 50px 50px; } .animate-dot{ animation: move-dot 8s linear infinite; } .animate-dot2{ animation: move-dot2 6s linear infinite; } @keyframes move-dot{ 0%{ background-position: 0 0, 50px 0, 100px 0, 150px 0; } 30%{ background-position: 50px 0, 0 0, 100px 0, 150px 0; } 60%{ background-position: 50px 0, 100px 0, 0 0, 150px 0; } 100%{ background-position: 50px 0, 100px 0, 150px 0, 0 0; } } @keyframes move-dot2{ 0%{ background-image: radial-gradient(circle,#0cf 15px,transparent), radial-gradient(circle,gray 15px,transparent), radial-gradient(circle,gray 15px,transparent), radial-gradient(circle,gray 15px,transparent); } 30%{ background-image: radial-gradient(circle,gray 15px,transparent), radial-gradient(circle,red 15px,transparent), radial-gradient(circle,gray 15px,transparent), radial-gradient(circle,gray 15px,transparent); } 60%{ background-image: radial-gradient(circle,gray 15px,transparent), radial-gradient(circle,gray 15px,transparent), radial-gradient(circle,yellow 15px,transparent), radial-gradient(circle,gray 15px,transparent); } 100%{ background-image: radial-gradient(circle,gray 15px,transparent), radial-gradient(circle,gray 15px,transparent), radial-gradient(circle,gray 15px,transparent), radial-gradient(circle,green 15px,transparent); } } </style> <div class="bg-dot black-theme animate-dot"></div> <div class="bg-dot black-theme animate-dot2"></div> 复制代码

棋盘背景以及棋盘背景随机动画

利用背景渐变实现棋盘图案核心代码

<style> .bg-qi{ margin-top: 20px; width: 200px; height: 200px; background-color: #eee; background-image: linear-gradient(45deg,rgba(0,0,0,.25) 25%,transparent 0,transparent 75%,rgba(0,0,0,.25) 0), linear-gradient(45deg,rgba(0,0,0,.25) 25%,transparent 0,transparent 75%,rgba(0,0,0,.25) 0); background-position: 0 0, 20px 20px; background-size: 40px 40px; box-shadow: 2px 2px 4px rgba(0,0,0,.4); } </style> <div class="bg-qi black-theme"></div> 复制代码

伪随机背景

利用背景渐变，keyframe动画，实现复杂的伪随机动画核心代码

<style> .bg-line-rand{ margin-top: 20px; width: 480px; height: 60px; background-color: #eee; background-image: linear-gradient(90deg,#fb3 11px, transparent 0), linear-gradient(90deg,#ab4 23px, transparent 0), linear-gradient(90deg,#655 41px, transparent 0); background-size: 41px 100%, 61px 100%, 83px 100%; box-shadow: 2px 2px 4px rgba(0,0,0,.4); } .bg-dot-rand{ margin-top: 20px; width: 200px; height: 200px; background-color: #eee; background-image: radial-gradient(circle,#fb3 5px, transparent 0), radial-gradient(circle,#ab4 13px, transparent 0), radial-gradient(circle,#655 31px, transparent 0); background-repeat: no-repeat; background-size: 101px 203px, 147px 60px, 373px 201px; box-shadow: 2px 2px 4px rgba(0,0,0,.4); } .animate1{ animation: move 4s linear infinite; } .animate2{ animation: move2 4s linear infinite; } @keyframes move{ 0%{ background-position: 0 0, 0 0, 0 0; } 50%{ background-position: -10px 0, 20px 0, 30px 0; } 100%{ background-position: 0 0, 30px 0, 10px 0; } } @keyframes move2{ 0%{ background-position: 0 0, 0 0, 0 0; } 50%{ background-position: -10px 30px, 20px 0, -40px 80px; } 100%{ background-position: 0 20px, 60px -20px, 10px 30px; } } </style> <div class="bg-line-rand black-theme"></div> <div class="bg-line-rand black-theme animate1"></div> <div class="bg-dot-rand black-theme animate2"></div> 复制代码

5.折角效果

知识点：linear-gradient

核心代码

<style> .fold{ margin-left: auto; margin-right: auto; margin-bottom: 20px; width: 200px; height: 80px; color: #fff; line-height: 80px; text-align: center; background: linear-gradient(to left bottom,transparent 50%,rgba(0,0,0,.5) 0) no-repeat 100% 0 / 2em 2em, linear-gradient(-135deg,transparent 1.4em,#06c 0); } .linear{ background: linear-gradient(to left bottom,transparent 50%,rgba(0,0,0,.5)) no-repeat 100% 0 / 2em 2em, linear-gradient(-135deg,transparent 1.4em,#06c); } </style> <div class="fold">折角效果哦</div> <div class="fold linear">折角效果哦</div> 复制代码

2.内阴影圆折角效果

核心代码

<style> .fold-1{ margin-left: auto; margin-right: auto; margin-bottom: 20px; position: relative; width: 200px; height: 80px; border-radius: .5em; color: #fff; line-height: 80px; text-align: center; background: linear-gradient(-150deg,transparent 1.5em, #58a 0); } .fold-1::before{ content: ""; position: absolute; top: 0; right: 0; background: linear-gradient(to left bottom,transparent 50%,rgba(0,0,0,.2) 0,rgba(0,0,0,.4)) 100% 0 no-repeat; width: 1.73em; height: 3em; transform: translateY(-1.3em) rotate(-30deg); transform-origin: bottom right; border-bottom-left-radius: inherit; box-shadow: -.2em .2em .3em -.1em rgba(0,0,0,.15); } </style> <div class="fold-1">折角效果哦</div> 复制代码

6.自适应文本的条纹背景

知识点：linear-gradient,line-height,background-origin

核心代码

<style> .stripe-bg{ padding: .5em; line-height: 1.5em; background: beige; background-size: auto 3em; background-origin: content-box; background-image: linear-gradient(rgba(0,0,0,.2) 50%, transparent 0); } .stripe-bg > p{ margin: 0; } </style> <div class="stripe-bg"> <p>hello you</p> <p>hello you</p> <p>hello you</p> <p>hello you</p> <p>hello you</p> </div> 复制代码

7.自定义的下划线实现

知识点linear-gridient

小伙伴们注意到了吗？默认的下划线会将文字穿过，而上面的不会呦！

核心代码

<style> .my-line{ line-height: 1.4em; background: linear-gradient(gray,gray) no-repeat; background-size: 100% 1px; background-position: 0 1.15em; text-shadow: .05em 0 #fff, -.05em 0 #fff; } </style> <div class=""><span class="my-line">i have your big apple.you have a too? hi hi hi.</span></div> 复制代码

最后

笔者3天后将推出开源的CMS系统，技术架构：

• 后台Node Koa redis JsonSchema
• 管理后台界面 vue-cli3 vue ts vuex antd-vue axios
• 客户端前台 react antd react-hooks axios

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