屌屌的写法。。

function htmlEncode(value){

  //create a in-memory div, set it's inner text(which jQuery automatically encodes)

  //then grab the encoded contents back out.  The div never exists on the page.

  return $('<div/>').text(value).html();

}

function htmlDecode(value){

  return $('<div/>').html(value).text();

}