截断保存HTML标记结构的字符串

function truncateHTMLString(htmlString, maxLength) {
  const tempElement = document.createElement('div');
  tempElement.innerHTML = htmlString;
  
  let truncatedHTMLString = '';
  let currentLength = 0;
  
  function traverseDOM(node) {
    if (currentLength >= maxLength) {
      return;
    }
    
    if (node.nodeType === Node.TEXT_NODE) {
      const remainingLength = maxLength - currentLength;
      const textContent = node.textContent;
      
      if (textContent.length <= remainingLength) {
        truncatedHTMLString += textContent;
        currentLength += textContent.length;
      } else {
        truncatedHTMLString += textContent.substring(0, remainingLength);
        currentLength += remainingLength;
      }
    } else {
      const tagName = node.tagName.toLowerCase();
      const clonedNode = node.cloneNode(false);
      
      truncatedHTMLString += `<${tagName}>`;
      
      for (const childNode of node.childNodes) {
        traverseDOM(childNode);
      }
      
      truncatedHTMLString += `</${tagName}>`;
    }
  }
  
  traverseDOM(tempElement);
  
  return truncatedHTMLString;
}