php+xml实现在线英文词典之添加词条的方法

<?xml version="1.0" encoding="utf-8"?>
<words>
<word>
 <en>boy</en>
 <ch>男孩</ch>
</word>
<word>
 <en>girl</en>
 <ch>女孩</ch>
</word>
<word>
 <en>teacher</en>
 <ch>老师</ch>
</word>
<word>
 <en>beauty</en>
 <ch>美女</ch>
</word>
</words>

<h2 style="color:green">在线英汉词典</h2>
<h4>查询英文单词</h4>
<form action="xmlprocess.php" method="post">
请输入英文单词<input type="text" name="enword" />
<input type="submit" value="查询" name="sub" />
</form>
<h4>添加英文单词</h4>
<form action="xmlprocess.php" method="post">
英文单词<input type="text" name="en_word" /><br />
中文意思<input type="text" name="ch_word" />
<input type="submit" value="添加" name="add">
</form>

<?php
//创建xml对象
$xmldoc = new DOMDocument();
$xmldoc->load("words.xml");
//查询
if(!empty($_POST['sub'])){
 $en_word = $_POST['enword'];
 $word = $xmldoc->getElementsByTagName("en");
 for($i=0;$i<$word->length;$i++){
  if($en_word==$word->item($i)->nodeValue){
   $_word = $xmldoc->getElementsByTagName("ch")->item($i)->nodeValue;
   break;
  }else{
   $_word = "找不到你所输入的单词";
  }
 }
 echo $_word;
}
//增加词条
if(!empty($_POST['add'])){
 $en_word = $_POST['en_word'];
 $ch_word = $_POST['ch_word'];
 //获取根节点
 $words = $xmldoc->getElementsByTagName("words")->item(0);
 //增加元素，并添加内容
 $new_word = $xmldoc->createElement("word");
 $new_word_en = $xmldoc->createElement("en");
 $new_word_en->nodeValue = $en_word;
 $new_word_ch = $xmldoc->createElement("ch");
 $new_word_ch->nodeValue = $ch_word;
 //元素之间挂载，意思是将子元素与父元素相连
 $new_word->appendChild($new_word_en);
 $new_word->appendChild($new_word_ch);
 $words->appendChild($new_word);
 //保存
 $xmldoc->save("words.xml");
}
?>