There is the solution if you need only outline without border. It's not mine. I got if from Bootstrap css file. If you specify outline: 1px auto certain_color, you'll get thin outer line around div of certain color. In this case the specified width has no matter, even if you specify 10 px width, anyway it will be thin line. The key word in mentioned rule is "auto". If you need outline with rounded corners and certain width, you may add css rule on border with needed width and same color. It makes outline thicker.

如果你想要浮雕效果，你可以这样做:

.embossed { background: #e5e5e5; height: 100px; width: 200px; border: #FFFFFF solid 1px; outline: #d0d0d0 solid 1px; margin: 15px; } .border-radius { border-radius: 20px 20px 20px 20px; -webkit-border-radius: 20px; -moz-border-radius: 20px; -khtml-border-radius: 20px; } .outline-radius { -moz-outline-radius: 21px; } <div class="embossed"></div> <div class="embossed border-radius"></div> <div class="embossed border-radius outline-radius">-MOZ ONLY</div>

我还没有找到一个工作周围有这个工作在其他浏览器。

编辑:你能做到这一点的唯一其他方法是使用盒子阴影，但如果你已经在该元素上有一个盒子阴影，这将不起作用。

我刚刚找到了一个很好的解决方案，在看了所有的回复后，我还没有看到它发布。所以，这就是我所做的:

我为类创建了一个CSS规则，并为该规则使用了一个伪类:focus。我设置outline: none来去掉Chrome默认使用的浅蓝色无边框半径的“outline”。然后，在同样的:focus伪类中，轮廓不再存在，我添加了半径和边界属性。导致以下结果

outline: none;
border-radius: 5px;
border: 2px solid maroon;

当用户通过选项卡选择元素时，有一个带有边界半径的栗色轮廓。

我有一个圆形边框的输入字段，想要改变焦点轮廓的颜色。我无法控制输入控件中可怕的方形轮廓。

所以我用了盒影。实际上我更喜欢阴影的平滑外观，但阴影可以被硬化以模拟圆形轮廓:

输入，输入:焦点{ 边界:没有; border - radius: 2分; Box-shadow: 0 0 0 1pt灰色; 大纲:没有; 过渡:1。; ｝ /*平滑的轮廓与盒子阴影:*/ .text1:专注{ 箱影:0 0 3pt 2pt矢车菊蓝; ｝ /*硬“轮廓”与盒子阴影:*/ .text2:专注{ 箱影:0 0 0 2pt红色; ｝ <输入class = " text1 " > < br > < br > <input type=text class="text2">

对这个基本问题的简单回答是否定的。唯一的跨浏览器选择是创建一个完成你想要的东西的黑客。在对已有的内容进行样式化时，这种方法确实存在一些潜在的问题，但与许多其他解决方案相比，它提供了更多的轮廓定制(偏移量、宽度、线条样式)。

在基本层面上，考虑以下静态示例(运行演示代码片段):

.outline { border: 2px dotted transparent; border-radius: 5px; display: inline-block; padding: 2px; margin: -4px; } /* :focus-within does not work in Edge or IE */ .outline:focus-within, .outline.edge { border-color: blue; } br { margin-bottom: 0.75rem; } <h3>Javascript-Free Demo</h3> <div class="outline edge"><input type="text" placeholder="I always have an outline"/></div><br><div class="outline"><input type="text" placeholder="I have an outline when focused"/></div> *<i>Doesn't work in Edge or IE</i><br><input type="text" placeholder="I have never have an outline" /> <p>Note that the outline does not increase the spacing between the outlined input and other elements around it. The margin (-4px) compensates for the space that the outlines padding (-2px) and width (2px) take up, a total of 4px.</p>

现在，在更高级的级别上，可以使用JavaScript引导给定类型或类的元素，以便将它们包装在一个div中，以模拟页面加载时的大纲。此外，可以建立事件绑定来显示或隐藏用户交互的大纲，就像这样(运行下面的代码片段或在JSFiddle中打开):

h3 { margin: 0; } div { box-sizing: border-box; } .flex { display: flex; } .clickable { cursor: pointer; } .box { background: red; border: 1px solid black; border-radius: 10px; height: 5rem; display: flex; align-items: center; text-align: center; color: white; font-weight: bold; padding: 0.5rem; margin: 1rem; } <h3>Javascript-Enabled Demo</h3> <div class="flex"> <div class="box outline-me">I'm outlined because I contain<br>the "outline-me" class</div> <div class="box clickable">Click me to toggle outline</div> </div> <hr> <input type="text" placeholder="I'm outlined when focused" /> <script> // Called on an element to wrap with an outline and passed a styleObject // the styleObject can contain the following outline properties: // style, width, color, offset, radius, bottomLeftRadius, // bottomRightRadius, topLeftRadius, topRightRadius // It then creates a new div with the properties specified and // moves the calling element into the div // The newly created wrapper div receives the class "simulated-outline" Element.prototype.addOutline = function (styleObject, hideOutline = true) { var element = this; // create a div for simulating an outline var outline = document.createElement('div'); // initialize css formatting var css = 'display:inline-block;'; // transfer any element margin to the outline div var margins = ['marginTop', 'marginBottom', 'marginLeft', 'marginRight']; var marginPropertyNames = { marginTop: 'margin-top', marginBottom: 'margin-bottom', marginLeft: 'margin-left', marginRight: 'margin-right' } var outlineWidth = Number.parseInt(styleObject.width); var outlineOffset = Number.parseInt(styleObject.offset); for (var i = 0; i < margins.length; ++i) { var computedMargin = Number.parseInt(getComputedStyle(element)[margins[i]]); var margin = computedMargin - outlineWidth - outlineOffset; css += marginPropertyNames[margins[i]] + ":" + margin + "px;"; } element.style.cssText += 'margin:0px !important;'; // compute css border style for the outline div var keys = Object.keys(styleObject); for (var i = 0; i < keys.length; ++i) { var key = keys[i]; var value = styleObject[key]; switch (key) { case 'style': var property = 'border-style'; break; case 'width': var property = 'border-width'; break; case 'color': var property = 'border-color'; break; case 'offset': var property = 'padding'; break; case 'radius': var property = 'border-radius'; break; case 'bottomLeftRadius': var property = 'border-bottom-left-radius'; break; case 'bottomRightRadius': var property = 'border-bottom-right-radius'; break; case 'topLeftRadius': var property = 'border-top-left-radius-style'; break; case 'topRightRadius': var property = 'border-top-right-radius'; break; } css += property + ":" + value + ';'; } // apply the computed css to the outline div outline.style.cssText = css; // add a class in case we want to do something with elements // receiving a simulated outline outline.classList.add('simulated-outline'); // place the element inside the outline div var parent = element.parentElement; parent.insertBefore(outline, element); outline.appendChild(element); // determine whether outline should be hidden by default or not if (hideOutline) element.hideOutline(); } Element.prototype.showOutline = function () { var element = this; // get a reference to the outline element that wraps this element var outline = element.getOutline(); // show the outline if one exists if (outline) outline.classList.remove('hide-outline'); } Element.prototype.hideOutline = function () { var element = this; // get a reference to the outline element that wraps this element var outline = element.getOutline(); // hide the outline if one exists if (outline) outline.classList.add('hide-outline'); } // Determines if this element has an outline. If it does, it returns the outline // element. If it doesn't have one, return null. Element.prototype.getOutline = function() { var element = this; var parent = element.parentElement; return (parent.classList.contains('simulated-outline')) ? parent : null; } // Determines the visiblity status of the outline, returning true if the outline is // visible and false if it is not. If the element has no outline, null is returned. Element.prototype.outlineStatus = function() { var element = this; var outline = element.getOutline(); if (outline === null) { return null; } else { return !outline.classList.contains('hide-outline'); } } // this embeds a style element in the document head for handling outline visibility var embeddedStyle = document.querySelector('#outline-styles'); if (!embeddedStyle) { var style = document.createElement('style'); style.innerText = ` .simulated-outline.hide-outline { border-color: transparent !important; } `; document.head.append(style); } /*########################## example usage ##########################*/ // add outline to all elements with "outline-me" class var outlineMeStyle = { style: 'dashed', width: '3px', color: 'blue', offset: '2px', radius: '5px' }; document.querySelectorAll('.outline-me').forEach((element)=>{ element.addOutline(outlineMeStyle, false); }); // make clickable divs get outlines var outlineStyle = { style: 'double', width: '4px', offset: '3px', color: 'red', radius: '10px' }; document.querySelectorAll('.clickable').forEach((element)=>{ element.addOutline(outlineStyle); element.addEventListener('click', (evt)=>{ var element = evt.target; (element.outlineStatus()) ? element.hideOutline() : element.showOutline(); }); }); // configure inputs to only have outline on focus document.querySelectorAll('input').forEach((input)=>{ var outlineStyle = { width: '2px', offset: '2px', color: 'black', style: 'dotted', radius: '10px' } input.addOutline(outlineStyle); input.addEventListener('focus', (evt)=>{ var input = evt.target; input.showOutline(); }); input.addEventListener('blur', (evt)=>{ var input = evt.target; input.hideOutline(); }); }); </script>

最后，让我重申一下，实现这种方法可能需要比我在演示中包含的更多的样式，特别是如果您已经样式化了想要概述的元素。

正如其他人所说，只有firefox支持这个功能。这里有一个工作，做同样的事情，甚至工作与虚线轮廓。

.has-outline { 显示:inline-block; 背景:# 51 ab9f; border - radius: 10 px; 填充:5 px; 位置:相对; ｝ .has-outline:{后 border - radius: 10 px; 填充:5 px; 边框:2px虚线#9dd5cf; 位置:绝对的; 内容:”; 上图:2 px; 左:2 px; 底部:2 px; 右:2 px; ｝ < div class = " has-outline”> 我能画出轮廓 < / div >