我知道这里有很多好的答案，但由于我实现了一个有点不同的方法，我想分享一下。

这段代码是一种非常安全的安全方法，因为转义处理程序依赖于浏览器，而不是函数。因此，如果将来发现新的漏洞，将覆盖此解决方案。

const decodeHTMLEntities = text => {
    // Create a new element or use one from cache, to save some element creation overhead
    const el = decodeHTMLEntities.__cache_data_element 
             = decodeHTMLEntities.__cache_data_element 
               || document.createElement('div');
    
    const enc = text
        // Prevent any mixup of existing pattern in text
        .replace(/⪪/g, '⪪#')
        // Encode entities in special format. This will prevent native element encoder to replace any amp characters
        .replace(/&([a-z1-8]{2,31}|#x[0-9a-f]+|#\d+);/gi, '⪪$1⪫');

    // Encode any HTML tags in the text to prevent script injection
    el.textContent = enc;

    // Decode entities from special format, back to their original HTML entities format
    el.innerHTML = el.innerHTML
        .replace(/⪪([a-z1-8]{2,31}|#x[0-9a-f]+|#\d+)⪫/gi, '&$1;')
        .replace(/#⪫/g, '⪫');
   
    // Get the decoded HTML entities
    const dec = el.textContent;
    
    // Clear the element content, in order to preserve a bit of memory (it is just the text may be pretty big)
    el.textContent = '';

    return dec;
}

// Example
console.log(decodeHTMLEntities("<script>alert('&awconint;&CounterClockwiseContourIntegral;&#x02233;&#8755;⪪#x02233⪫');</script>"));
// Prints: <script>alert('∳∳∳∳⪪##x02233⪫');</script>

顺便说一下，我选择使用字符⪪和⪫，因为它们很少被使用，因此通过匹配它们影响性能的几率显著降低。

jQuery将为您编码和解码。但是，您需要使用textarea标签，而不是div。

var str1 = 'One & two & three'; var str2 = "One &amp; two &amp; three"; $(document).ready(function() { $("#encoded").text(htmlEncode(str1)); $("#decoded").text(htmlDecode(str2)); }); function htmlDecode(value) { return $("<textarea/>").html(value).text(); } function htmlEncode(value) { return $('<textarea/>').text(value).html(); } <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script> <div id="encoded"></div> <div id="decoded"></div>

其他答案都有问题。

document.createElement('div')方法(包括使用jQuery的方法)执行传递给它的任何javascript(一个安全问题)，DOMParser.parseFromString()方法修饰空白。这是一个纯javascript解决方案，没有任何问题:

function htmlDecode(html) {
    var textarea = document.createElement("textarea");
    html= html.replace(/\r/g, String.fromCharCode(0xe000)); // Replace "\r" with reserved unicode character.
    textarea.innerHTML = html;
    var result = textarea.value;
    return result.replace(new RegExp(String.fromCharCode(0xe000), 'g'), '\r');
}

TextArea是专门用来避免执行js代码。它通过了这些:

htmlDecode('&lt;&amp;&nbsp;&gt;'); // returns "<& >" with non-breaking space.
htmlDecode('  '); // returns "  "
htmlDecode('<img src="dummy" onerror="alert(\'xss\')">'); // Does not execute alert()
htmlDecode('\r\n') // returns "\r\n", doesn't lose the \r like other solutions.

不客气只是一个信使……全部归功于ourcodeworld.com，链接如下。

window.htmlentities = {
        /**
         * Converts a string to its html characters completely.
         *
         * @param {String} str String with unescaped HTML characters
         **/
        encode : function(str) {
            var buf = [];

            for (var i=str.length-1;i>=0;i--) {
                buf.unshift(['&#', str[i].charCodeAt(), ';'].join(''));
            }

            return buf.join('');
        },
        /**
         * Converts an html characterSet into its original character.
         *
         * @param {String} str htmlSet entities
         **/
        decode : function(str) {
            return str.replace(/&#(\d+);/g, function(match, dec) {
                return String.fromCharCode(dec);
            });
        }
    };

出处:https://ourcodeworld.com/articles/read/188/encode-and-decode-html-entities-using-pure-javascript

CMS的答案很好，除非你想要取消转义的HTML非常长，超过65536个字符。因为在Chrome中，内部HTML被分割成许多子节点，每个子节点最长65536个，你需要将它们连接起来。这个函数也适用于很长的字符串:

function unencodeHtmlContent(escapedHtml) {
  var elem = document.createElement('div');
  elem.innerHTML = escapedHtml;
  var result = '';
  // Chrome splits innerHTML into many child nodes, each one at most 65536.
  // Whereas FF creates just one single huge child node.
  for (var i = 0; i < elem.childNodes.length; ++i) {
    result = result + elem.childNodes[i].nodeValue;
  }
  return result;
}

有关innerHTML最大长度的更多信息，请参阅以下答案:https://stackoverflow.com/a/27545633/694469

// decode-html.js v1
function decodeHtml(html) {
    const textarea = document.createElement('textarea');
    textarea.innerHTML = html;
    const decodedHtml = textarea.textContent;
    textarea.remove();
    return decodedHtml;
};

// encode-html.js v1
function encodeHtml(html) {
    const textarea = document.createElement('textarea');
    textarea.textContent = html;
    const encodedHtml = textarea.innerHTML;
    textarea.remove();
    return encodedHtml;
};

// example of use:
let htmlDecoded = 'one & two & three';
let htmlEncoded = 'one & two & three';

console.log(1, htmlDecoded);
console.log(2, encodeHtml(htmlDecoded));

console.log(3, htmlEncoded);
console.log(4, decodeHtml(htmlEncoded));