function format(DOMNode $node, $treeIndex = 0){ //不格式化的标签 if (in_array($node->nodeName, array("title", "p", "span"))) return; if ($node->hasChildNodes()) { $treeIndex++; $tabStart = "rn" . str_repeat("TTT", $treeIndex); $tabEnd = "rn" . str_repeat("EEE", $treeIndex - 1); $i = 0; while ($childNode = $node->childNodes->item($i++)) { if ($childNode->nodeType == XML_TEXT_NODE) { if (ctype_space($childNode->nodeValue)) { $node->removeChild($childNode); $i--; continue; } $childNode->nodeValue = trim($childNode->nodeValue); } $node->insertBefore($node->ownerDocument->createTextNode($tabStart), $childNode); $i++; $this->format($childNode, $treeIndex); }; $node->appendChild($node->ownerDocument->createTextNode($tabEnd)); }}$html = '<!DOCTYPE html><html><head><meta charset="utf-8"><title></title></head><body></body></html>';$doc = new DOMDocument(); //$doc->formatOutput = true; //不知道是不是我的理解问题，这个选项格式化出来的并不完美$doc->loadHTML($html); format($doc->documentElement);echo $doc->saveHTML();