Javascipt高亮显示关键词，或添加链接

实现原理：

在页面加载完成时获取页面来源（document.referrer），并分析搜索引擎关键词，然后获取页面上所有元素，递归查询是否含有搜索关键字，如果有，就创建一个 span 元素，并应用关键词样式，替换原有节点。

<script>
var allCount=0;

function highlightWord(node,word,realUrl) {

      // Iterate into this nodes childNodes
	if (node.hasChildNodes&&allCount<4) {
		var hi_cn;
		for (hi_cn=0;hi_cn<node.childNodes.length;hi_cn++) {
			highlightWord(node.childNodes[hi_cn],word,realUrl);
		}
	}
    // And do this node itself

    if (node.nodeType == 3) { // text node
		tempNodeVal = node.nodeValue.toLowerCase();
		tempWordVal = word.toLowerCase();
		if (tempNodeVal.indexOf(tempWordVal) != -1&&allCount<4) {
			pn = node.parentNode;
			if (pn.className != "searchword") {
				// word has not already been highlighted!
				nv = node.nodeValue;
				ni = tempNodeVal.indexOf(tempWordVal);
				// Create a load of replacement nodes
				before = document.createTextNode(nv.substr(0,ni));
				docWordVal = nv.substr(ni,word.length);
				after = document.createTextNode(nv.substr(ni+word.length));
				hiwordtext = document.createTextNode(docWordVal);
				hiword = document.createElement("a");
				hiword.className = "searchword";
				hiword.setAttribute("href",realUrl);
				hiword.appendChild(hiwordtext);
				pn.insertBefore(before,node);
				pn.insertBefore(hiword,node);
				pn.insertBefore(after,node);
				pn.removeChild(node);
				allCount++;
			}
		}
      }

}

function googleSearchHighlight() {
      if (!document.createElement) return;
      ref = document.referrer;
      if (ref.indexOf('?') == -1) return;
      qs = ref.substr(ref.indexOf('?')+1);
      qsa = qs.split('&');
      for (i=0;i<qsa.length;i++) {
			qsip = qsa[i].split('=');
			if (qsip.length == 1) continue;
			if (qsip[0] == 'q' || qsip[0] == 'p') { // q= for Google, p= for Yahoo
				words = unescape(decodeURIComponent(qsip[1].replace(/\+/g,' '))).split(/\s+/);
				for (w=0;w<words.length;w++) {

					 highlightWord(document.getElementsByTagName("body")[0],words[w]);
				}
			}
      }

}

function testAddlink() {
		var wordList = new Array("用户","命令"); 
		var linkList=new Array("http://www.116tea.cn","http://www.iteye.com","http://www.163.com");
		for (w=0;w<wordList.length;w++) {
			allCount=0;
			highlightWord(document.getElementsByTagName("body")[0],wordList[w],linkList[w]);
		}
} 
window.onload = testAddlink;

</script></html>