<script type="text/javascript">

function HTMLEncode(html)

{

var temp = document.createElement ("div");

(temp.textContent != null) ? (temp.textContent = html) : (temp.innerText = html);

var output = temp.innerHTML;

temp = null;

return output;

} 

function HTMLDecode(text)

{

var temp = document.createElement("div");

temp.innerHTML = text;

var output = temp.innerText || temp.textContent;

temp = null;

return output;

} 

var html = "<br>dffdfqqqqq";

var encodeHTML = HTMLEncode(html);

alert("方法一：" +encodeHTML);

var decodeHTML = HTMLDecode(encodeHTML);

alert("方法一：" +decodeHTML);

</script>