你可以使用我的插件来实现这个目的。

JQuery:

(function() { $.pseudoElements = { length: 0 }; var setPseudoElement = function(parameters) { if (typeof parameters.argument === 'object' || (parameters.argument !== undefined && parameters.property !== undefined)) { for (var element of parameters.elements.get()) { if (!element.pseudoElements) element.pseudoElements = { styleSheet: null, before: { index: null, properties: null }, after: { index: null, properties: null }, id: null }; var selector = (function() { if (element.pseudoElements.id !== null) { if (Number(element.getAttribute('data-pe--id')) !== element.pseudoElements.id) element.setAttribute('data-pe--id', element.pseudoElements.id); return '[data-pe--id="' + element.pseudoElements.id + '"]::' + parameters.pseudoElement; } else { var id = $.pseudoElements.length; $.pseudoElements.length++ element.pseudoElements.id = id; element.setAttribute('data-pe--id', id); return '[data-pe--id="' + id + '"]::' + parameters.pseudoElement; }; })(); if (!element.pseudoElements.styleSheet) { if (document.styleSheets[0]) { element.pseudoElements.styleSheet = document.styleSheets[0]; } else { var styleSheet = document.createElement('style'); document.head.appendChild(styleSheet); element.pseudoElements.styleSheet = styleSheet.sheet; }; }; if (element.pseudoElements[parameters.pseudoElement].properties && element.pseudoElements[parameters.pseudoElement].index) { element.pseudoElements.styleSheet.deleteRule(element.pseudoElements[parameters.pseudoElement].index); }; if (typeof parameters.argument === 'object') { parameters.argument = $.extend({}, parameters.argument); if (!element.pseudoElements[parameters.pseudoElement].properties && !element.pseudoElements[parameters.pseudoElement].index) { var newIndex = element.pseudoElements.styleSheet.rules.length || element.pseudoElements.styleSheet.cssRules.length || element.pseudoElements.styleSheet.length; element.pseudoElements[parameters.pseudoElement].index = newIndex; element.pseudoElements[parameters.pseudoElement].properties = parameters.argument; }; var properties = ''; for (var property in parameters.argument) { if (typeof parameters.argument[property] === 'function') element.pseudoElements[parameters.pseudoElement].properties[property] = parameters.argument[property](); else element.pseudoElements[parameters.pseudoElement].properties[property] = parameters.argument[property]; }; for (var property in element.pseudoElements[parameters.pseudoElement].properties) { properties += property + ': ' + element.pseudoElements[parameters.pseudoElement].properties[property] + ' !important; '; }; element.pseudoElements.styleSheet.addRule(selector, properties, element.pseudoElements[parameters.pseudoElement].index); } else if (parameters.argument !== undefined && parameters.property !== undefined) { if (!element.pseudoElements[parameters.pseudoElement].properties && !element.pseudoElements[parameters.pseudoElement].index) { var newIndex = element.pseudoElements.styleSheet.rules.length || element.pseudoElements.styleSheet.cssRules.length || element.pseudoElements.styleSheet.length; element.pseudoElements[parameters.pseudoElement].index = newIndex; element.pseudoElements[parameters.pseudoElement].properties = {}; }; if (typeof parameters.property === 'function') element.pseudoElements[parameters.pseudoElement].properties[parameters.argument] = parameters.property(); else element.pseudoElements[parameters.pseudoElement].properties[parameters.argument] = parameters.property; var properties = ''; for (var property in element.pseudoElements[parameters.pseudoElement].properties) { properties += property + ': ' + element.pseudoElements[parameters.pseudoElement].properties[property] + ' !important; '; }; element.pseudoElements.styleSheet.addRule(selector, properties, element.pseudoElements[parameters.pseudoElement].index); }; }; return $(parameters.elements); } else if (parameters.argument !== undefined && parameters.property === undefined) { var element = $(parameters.elements).get(0); var windowStyle = window.getComputedStyle( element, '::' + parameters.pseudoElement ).getPropertyValue(parameters.argument); if (element.pseudoElements) { return $(parameters.elements).get(0).pseudoElements[parameters.pseudoElement].properties[parameters.argument] || windowStyle; } else { return windowStyle || null; }; } else { console.error('Invalid values!'); return false; }; }; $.fn.cssBefore = function(argument, property) { return setPseudoElement({ elements: this, pseudoElement: 'before', argument: argument, property: property }); }; $.fn.cssAfter = function(argument, property) { return setPseudoElement({ elements: this, pseudoElement: 'after', argument: argument, property: property }); }; })(); $(function() { $('.element').cssBefore('content', '"New before!"'); }); .element { width: 480px; margin: 0 auto; border: 2px solid red; } .element::before { content: 'Old before!'; } <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script> <div class="element"></div>

应该指定值，就像在jQuery.css的普通函数中一样

此外，你还可以获得pseudo-element参数的值，就像在jQuery.css的普通函数中一样:

console.log( $(element).cssBefore(parameter) );

JS:

(function() { document.pseudoElements = { length: 0 }; var setPseudoElement = function(parameters) { if (typeof parameters.argument === 'object' || (parameters.argument !== undefined && parameters.property !== undefined)) { if (!parameters.element.pseudoElements) parameters.element.pseudoElements = { styleSheet: null, before: { index: null, properties: null }, after: { index: null, properties: null }, id: null }; var selector = (function() { if (parameters.element.pseudoElements.id !== null) { if (Number(parameters.element.getAttribute('data-pe--id')) !== parameters.element.pseudoElements.id) parameters.element.setAttribute('data-pe--id', parameters.element.pseudoElements.id); return '[data-pe--id="' + parameters.element.pseudoElements.id + '"]::' + parameters.pseudoElement; } else { var id = document.pseudoElements.length; document.pseudoElements.length++ parameters.element.pseudoElements.id = id; parameters.element.setAttribute('data-pe--id', id); return '[data-pe--id="' + id + '"]::' + parameters.pseudoElement; }; })(); if (!parameters.element.pseudoElements.styleSheet) { if (document.styleSheets[0]) { parameters.element.pseudoElements.styleSheet = document.styleSheets[0]; } else { var styleSheet = document.createElement('style'); document.head.appendChild(styleSheet); parameters.element.pseudoElements.styleSheet = styleSheet.sheet; }; }; if (parameters.element.pseudoElements[parameters.pseudoElement].properties && parameters.element.pseudoElements[parameters.pseudoElement].index) { parameters.element.pseudoElements.styleSheet.deleteRule(parameters.element.pseudoElements[parameters.pseudoElement].index); }; if (typeof parameters.argument === 'object') { parameters.argument = (function() { var cloneObject = typeof parameters.argument.pop === 'function' ? [] : {}; for (var property in parameters.argument) { cloneObject[property] = parameters.argument[property]; }; return cloneObject; })(); if (!parameters.element.pseudoElements[parameters.pseudoElement].properties && !parameters.element.pseudoElements[parameters.pseudoElement].index) { var newIndex = parameters.element.pseudoElements.styleSheet.rules.length || parameters.element.pseudoElements.styleSheet.cssRules.length || parameters.element.pseudoElements.styleSheet.length; parameters.element.pseudoElements[parameters.pseudoElement].index = newIndex; parameters.element.pseudoElements[parameters.pseudoElement].properties = parameters.argument; }; var properties = ''; for (var property in parameters.argument) { if (typeof parameters.argument[property] === 'function') parameters.element.pseudoElements[parameters.pseudoElement].properties[property] = parameters.argument[property](); else parameters.element.pseudoElements[parameters.pseudoElement].properties[property] = parameters.argument[property]; }; for (var property in parameters.element.pseudoElements[parameters.pseudoElement].properties) { properties += property + ': ' + parameters.element.pseudoElements[parameters.pseudoElement].properties[property] + ' !important; '; }; parameters.element.pseudoElements.styleSheet.addRule(selector, properties, parameters.element.pseudoElements[parameters.pseudoElement].index); } else if (parameters.argument !== undefined && parameters.property !== undefined) { if (!parameters.element.pseudoElements[parameters.pseudoElement].properties && !parameters.element.pseudoElements[parameters.pseudoElement].index) { var newIndex = parameters.element.pseudoElements.styleSheet.rules.length || parameters.element.pseudoElements.styleSheet.cssRules.length || parameters.element.pseudoElements.styleSheet.length; parameters.element.pseudoElements[parameters.pseudoElement].index = newIndex; parameters.element.pseudoElements[parameters.pseudoElement].properties = {}; }; if (typeof parameters.property === 'function') parameters.element.pseudoElements[parameters.pseudoElement].properties[parameters.argument] = parameters.property(); else parameters.element.pseudoElements[parameters.pseudoElement].properties[parameters.argument] = parameters.property; var properties = ''; for (var property in parameters.element.pseudoElements[parameters.pseudoElement].properties) { properties += property + ': ' + parameters.element.pseudoElements[parameters.pseudoElement].properties[property] + ' !important; '; }; parameters.element.pseudoElements.styleSheet.addRule(selector, properties, parameters.element.pseudoElements[parameters.pseudoElement].index); }; } else if (parameters.argument !== undefined && parameters.property === undefined) { var windowStyle = window.getComputedStyle( parameters.element, '::' + parameters.pseudoElement ).getPropertyValue(parameters.argument); if (parameters.element.pseudoElements) { return parameters.element.pseudoElements[parameters.pseudoElement].properties[parameters.argument] || windowStyle; } else { return windowStyle || null; }; } else { console.error('Invalid values!'); return false; }; }; Object.defineProperty(Element.prototype, 'styleBefore', { enumerable: false, value: function(argument, property) { return setPseudoElement({ element: this, pseudoElement: 'before', argument: argument, property: property }); } }); Object.defineProperty(Element.prototype, 'styleAfter', { enumerable: false, value: function(argument, property) { return setPseudoElement({ element: this, pseudoElement: 'after', argument: argument, property: property }); } }); })(); document.querySelector('.element').styleBefore('content', '"New before!"'); .element { width: 480px; margin: 0 auto; border: 2px solid red; } .element::before { content: 'Old before!'; } <div class="element"></div>

GitHub: https://github.com/yuri-spivak/managing-the-properties-of-pseudo-elements/

根据克里斯蒂安的建议，你还可以这样做:

$('head').append("<style>.span::after{ content:'bar' }</style>");

一种有效但不太有效的方法是在文档中添加带有新内容的规则，并用类引用它。根据需要，类可能需要为内容中的每个值提供唯一的id。

$("<style type='text/css'>span.id-after:after{content:bar;}</style>").appendTo($("head"));
$('span').addClass('id-after');

我总是添加我自己的utils函数，就像这样。

function setPseudoElContent(selector, value) {    
    document.styleSheets[0].addRule(selector, 'content: "' + value + '";');
}

setPseudoElContent('.class::after', 'Hello World!');

或使用ES6功能:

const setPseudoElContent = (selector, value) => {    
    document.styleSheets[0].addRule(selector, `content: "${value}";`);
}

setPseudoElContent('.class::after', 'Hello World!');

您可以创建一个伪属性，也可以使用一个现有的属性，并在伪元素的样式表中继承它。

var switched = false; // Enable color switching setInterval(function () { var color = switched ? 'red' : 'darkred'; var element = document.getElementById('arrow'); element.style.backgroundColor = color; // Managing pseudo-element's css // using inheritance. element.style.borderLeftColor = color; switched = !switched; }, 1000); .arrow { /* SET FICTIONAL PROPERTY */ border-left-color:red; background-color:red; width:1em; height:1em; display:inline-block; position:relative; } .arrow:after { border-top:1em solid transparent; border-right:1em solid transparent; border-bottom:1em solid transparent; border-left:1em solid transparent; /* INHERIT PROPERTY */ border-left-color:inherit; content:""; width:0; height:0; position:absolute; left:100%; top:-50%; } <span id="arrow" class="arrow"></span>

似乎它对“content”属性不起作用:(

$ (' .span ')。attr(“data-txt”、“foo”); $ (' .span ')。点击(函数(){ (美元)。Attr ('data-txt'，"任何其他文本"); }) .span { ｝ .span:{后 内容:attr (data-txt); ｝ < script src = " https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js " > < /脚本> < div class =“跨度”> < / div >