html mysql special character

function html_encode(str)   
{   
  var s = "";   
  if (str.length == 0) return "";   
  s = str.replace(/&/g, "&");   
  s = s.replace(/</g, "&lt;");   
  s = s.replace(/>/g, "&gt;");   
  //s = s.replace(/ /g, "&nbsp;");   
  s = s.replace(/\‘/g, "&#39;");   
  s = s.replace(/\"/g, "&quot;");   
  //s = s.replace(/\n/g, "<br>");   
  return s;   
}   
 
function html_decode(str)   
{   
  var s = "";   
  if (str.length == 0) return "";   
  s = str.replace(/&amp;/g, "&");   
  s = s.replace(/&lt;/g, "<");   
  s = s.replace(/&gt;/g, ">");   
  s = s.replace(/&nbsp;/g, " ");   
  s = s.replace(/&#39;/g, "\‘");   
  s = s.replace(/&quot;/g, "\"");   
  s = s.replace(/<br>/g, "\n");   
  return s;   
}