字节跳动最爱考的前端面试题：CSS 基础

2023-02-21 09:38:02html-css011

字节跳动最爱考的前端面试题：CSS 基础,第1张

参考链接： juejin.im/post/5e8d52…

animation、transition、transform、translate 这几个属性要搞清楚：

水平居中：

垂直居中

BFC 是块级格式上下文，IFC 是行内格式上下文：

不会，因为 BFC 是页面中一个独立的隔离容器，其内部的元素不会与外部的元素相互影响，比如两个 div，上面的 div 设置了 float，那么如果下面的元素不是 BFC，也没有设置 float，会形成对上面的元素进行包裹内容的情况，如果设置了下面元素为 overflow：hidden；属性那么就能够实现经典的两列布局，左边内容固定宽度，右边因为是 BFC 所以会进行自适应。

box-sizing 属性可以被用来调整这些表现:

BFC（Block Formatting Context）格式化上下文，是 Web 页面中盒模型布局的 CSS 渲染模式，指一个独立的渲染区域或者说是一个隔离的独立容器。

五种：

BFC 的特性：

CSS盒模型本质上是一个盒子，封装周围的HTML元素，它包括：外边距（margin）、边框（border）、内边距（padding）、实际内容（content）四个属性。 CSS盒模型： 标准模型 + IE模型

标准盒子模型：宽度=内容的宽度（content）+ border + padding

低版本IE盒子模型：宽度=内容宽度（content+border+padding），如何设置成 IE 盒子模型:

static：无特殊定位，对象遵循正常文档流。top，right，bottom，left等属性不会被应用。 relative：对象遵循正常文档流，但将依据top，right，bottom，left等属性在正常文档流中偏移位置。而其层叠通过z-index属性定义。 absolute：对象脱离正常文档流，使用top，right，bottom，left等属性进行绝对定位。而其层叠通过z-index属性定义。 fixed：对象脱离正常文档流，使用top，right，bottom，left等属性以窗口为参考点进行定位，当出现滚动条时，对象不会随着滚动。而其层叠通过z-index属性定义。 sticky：具体是类似 relative 和 fixed，在 viewport 视口滚动到阈值之前应用 relative，滚动到阈值之后应用 fixed 布局，由 top 决定。

问：为什么会有这种现象？你能解释一下吗

是由块级格式上下文决定的，BFC，元素在 BFC 中会进行上下排列，然后垂直距离由 margin 决定，并且会发生重叠，具体表现为同正取最大的，同负取绝对值最大的，一正一负，相加

BFC 是页面中一个独立的隔离容器，内部的子元素不会影响到外部的元素。

不清楚浮动会发生高度塌陷：浮动元素父元素高度自适应（父元素不写高度时，子元素写了浮动后，父元素会发生高度塌陷）

了解更多加入我们前端学习圈

HTML代码

<head>

<title>用CSS3动画给一个小球创建跳跃的动画效果</title>

</head>

<body>

</div>

</section>

</body>

</html>

CSS代码（创建一个与html同目录的index.css文件）

#ballWrapper{position:fixedtop:35%left:50%z-index:100margin-left:-70pxwidth:140pxheight:300pxcursor:pointer-webkit-transition:all 5s linear 0s-moz-transition:all 5s linear 0stransition:all 5s linear 0s-webkit-transform:scale(1)-moz-transform:scale(1)-o-transform:scale(1)transform:scale(1)-ms-transform:scale(1)}

#ballWrapper:active{cursor:pointer-webkit-transform:scale(0)-moz-transform:scale(0)-o-transform:scale(0)transform:scale(0)-ms-transform:scale(0)}

#ball{position:absolutetop:0z-index:11width:140pxheight:140pxborder-radius:70pxbackground:#bbbbackground:url(data:image/svg+xml background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(187,187,187,1)), color-stop(99%,rgba(119,119,119,1))) background: -webkit-linear-gradient(top, rgba(187,187,187,1) 0%,rgba(119,119,119,1) 99%) background: -o-linear-gradient(top, rgba(187,187,187,1) 0%,rgba(119,119,119,1) 99%) background: -ms-linear-gradient(top, rgba(187,187,187,1) 0%,rgba(119,119,119,1) 99%) background: linear-gradient(top, rgba(187,187,187,1) 0%,rgba(119,119,119,1) 99%) box-shadow: inset 0 -5px 15px rgba(255,255,255,0.4), inset -2px -1px 40px rgba(0,0,0,0.4), 0 0 1px #000 cursor: pointer base64,PD94bWwgdmVyc2lvbj0iMS4wIiA/Pgo8c3ZnIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgd2lkdGg9IjEwMCUiIGhlaWdodD0iMTAwJSIgdmlld0JveD0iMCAwIDEgMSIgcHJlc2VydmVBc3BlY3RSYXRpbz0ibm9uZSI+CiAgPGxpbmVhckdyYWRpZW50IGlkPSJncmFkLXVjZ2ctZ2VuZXJhdGVkIiBncmFkaWVudFVuaXRzPSJ1c2VyU3BhY2VPblVzZSIgeDE9IjAlIiB5MT0iMCUiIHgyPSIwJSIgeTI9IjEwMCUiPgogICAgPHN0b3Agb2Zmc2V0PSIwJSIgc3RvcC1jb2xvcj0iI2JiYmJiYiIgc3RvcC1vcGFjaXR5PSIxIi8+CiAgICA8c3RvcCBvZmZzZXQ9Ijk5JSIgc3RvcC1jb2xvcj0iIzc3Nzc3NyIgc3RvcC1vcGFjaXR5PSIxIi8+CiAgPC9saW5lYXJHcmFkaWVudD4KICA8cmVjdCB4PSIwIiB5PSIwIiB3aWR0aD0iMSIgaGVpZ2h0PSIxIiBmaWxsPSJ1cmwoI2dyYWQtdWNnZy1nZW5lcmF0ZWQpIiAvPgo8L3N2Zz4=)background:-moz-linear-gradient(top,rgba(187,187,187,1) 0,rgba(119,119,119,1) 99%)filter:progid:DXImageTransform.Microsoft.gradient( startColorstr='#bbbbbb', endColorstr='#777777', GradientType=0 )-webkit-animation:jump 1s infinite-moz-animation:jump 1s infinite-o-animation:jump 1s infinite-ms-animation:jump 1s infiniteanimation:jump 1s infinite}

#ball::after{position:absolutetop:10pxleft:30pxz-index:10width:80pxheight:40pxborder-radius:40px/20pxbackground:url(data:image/svg+xml background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(232,232,232,1)), color-stop(1%,rgba(232,232,232,1)), color-stop(100%,rgba(255,255,255,0))) background: -webkit-linear-gradient(top, rgba(232,232,232,1) 0%,rgba(232,232,232,1) 1%,rgba(255,255,255,0) 100%) background: -o-linear-gradient(top, rgba(232,232,232,1) 0%,rgba(232,232,232,1) 1%,rgba(255,255,255,0) 100%) background: -ms-linear-gradient(top, rgba(232,232,232,1) 0%,rgba(232,232,232,1) 1%,rgba(255,255,255,0) 100%) background: linear-gradient(top, rgba(232,232,232,1) 0%,rgba(232,232,232,1) 1%,rgba(255,255,255,0) 100%) content: "" base64,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)background:-moz-linear-gradient(top,rgba(232,232,232,1) 0,rgba(232,232,232,1) 1%,rgba(255,255,255,0) 100%)filter:progid:DXImageTransform.Microsoft.gradient( startColorstr='#e8e8e8', endColorstr='#00ffffff', GradientType=0 )}

#ballShadow{position:absolutebottom:0left:50%z-index:10margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-webkit-transform:scaleY(.3)-moz-transform:scaleY(.3)-o-transform:scaleY(.3)transform:scaleY(.3)-ms-transform:scaleY(.3)-webkit-animation:shrink 1s infinite-moz-animation:shrink 1s infinite-o-animation:shrink 1s infinite-ms-animation:shrink 1s infiniteanimation:shrink 1s infinite}

@-webkit-keyframes jump{0%{top:0-webkit-animation-timing-function:ease-in}

50%{top:140pxheight:140px-webkit-animation-timing-function:ease-out}

55%{top:160pxheight:120pxborder-radius:70px/60px-webkit-animation-timing-function:ease-in}

65%{top:120pxheight:140pxborder-radius:70px-webkit-animation-timing-function:ease-out}

95%{top:0-webkit-animation-timing-function:ease-in}

100%{top:0-webkit-animation-timing-function:ease-in}

}

@-moz-keyframes jump{0%{top:0-moz-animation-timing-function:ease-in}

50%{top:140pxheight:140px-moz-animation-timing-function:ease-out}

55%{top:160pxheight:120pxborder-radius:70px/60px-moz-animation-timing-function:ease-in}

65%{top:120pxheight:140pxborder-radius:70px-moz-animation-timing-function:ease-out}

95%{top:0-moz-animation-timing-function:ease-in}

100%{top:0-moz-animation-timing-function:ease-in}

}

@-o-keyframes jump{0%{top:0-o-animation-timing-function:ease-in}

50%{top:140pxheight:140px-o-animation-timing-function:ease-out}

55%{top:160pxheight:120pxborder-radius:70px/60px-o-animation-timing-function:ease-in}

65%{top:120pxheight:140pxborder-radius:70px-o-animation-timing-function:ease-out}

95%{top:0-o-animation-timing-function:ease-in}

100%{top:0-o-animation-timing-function:ease-in}

}

@-ms-keyframes jump{0%{top:0-ms-animation-timing-function:ease-in}

50%{top:140pxheight:140px-ms-animation-timing-function:ease-out}

55%{top:160pxheight:120pxborder-radius:70px/60px-ms-animation-timing-function:ease-in}

65%{top:120pxheight:140pxborder-radius:70px-ms-animation-timing-function:ease-out}

95%{top:0-ms-animation-timing-function:ease-in}

100%{top:0-ms-animation-timing-function:ease-in}

}

@keyframes jump{0%{top:0animation-timing-function:ease-in}

50%{top:140pxheight:140pxanimation-timing-function:ease-out}

55%{top:160pxheight:120pxborder-radius:70px/60pxanimation-timing-function:ease-in}

65%{top:120pxheight:140pxborder-radius:70pxanimation-timing-function:ease-out}

95%{top:0animation-timing-function:ease-in}

100%{top:0animation-timing-function:ease-in}

}

@-webkit-keyframes shrink{0%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-webkit-animation-timing-function:ease-in}

50%{bottom:30pxmargin-left:-10pxwidth:20pxheight:5pxborder-radius:20pxbackground:rgba(20,20,20,.3)box-shadow:0 0 20px 35px rgba(20,20,20,.3)-webkit-animation-timing-function:ease-out}

100%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-webkit-animation-timing-function:ease-in}

}

@-moz-keyframes shrink{0%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-moz-animation-timing-function:ease-in}

50%{bottom:30pxmargin-left:-10pxwidth:20pxheight:5pxborder-radius:20pxbackground:rgba(20,20,20,.3)box-shadow:0 0 20px 35px rgba(20,20,20,.3)-moz-animation-timing-function:ease-out}

100%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-moz-animation-timing-function:ease-in}

}

@-o-keyframes shrink{0%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-o-animation-timing-function:ease-in}

50%{bottom:30pxmargin-left:-10pxwidth:20pxheight:5pxborder-radius:20pxbackground:rgba(20,20,20,.3)box-shadow:0 0 20px 35px rgba(20,20,20,.3)-o-animation-timing-function:ease-out}

100%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-o-animation-timing-function:ease-in}

}

@-ms-keyframes shrink{0%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-ms-animation-timing-function:ease-in}

50%{bottom:30pxmargin-left:-10pxwidth:20pxheight:5pxborder-radius:20pxbackground:rgba(20,20,20,.3)box-shadow:0 0 20px 35px rgba(20,20,20,.3)-ms-animation-timing-function:ease-out}

100%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-ms-animation-timing-function:ease-in}

}

@keyframes shrink{0%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)animation-timing-function:ease-in}

50%{bottom:30pxmargin-left:-10pxwidth:20pxheight:5pxborder-radius:20pxbackground:rgba(20,20,20,.3)box-shadow:0 0 20px 35px rgba(20,20,20,.3)animation-timing-function:ease-out}

100%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)animation-timing-function:ease-in}

}

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