javascript encode或者decode html

function myHTMLEnCode(str)
{
var s = "";
if (str.length == 0) return "";
s = str.replace(/&/g, "&");
s = s.replace(/</g, "<");
s = s.replace(/>/g, ">");
s = s.replace(/ /g," ");
s = s.replace(/\'/g, "'");
s = s.replace(/\"/g, """);
//s = s.replace(/\n/g, "<br>");
return s;  
}
function myHTMLDeCode(str)
{
var s="";
if(str.length ==0) return "";
s = str.replace(/&/g, "&");
s = s.replace(/</g, "<");
s = s.replace(/>/g, ">");
s = s.replace(/ /g, " ");
s = s.replace(/'/g, "\'");
s = s.replace(/"/g, "\"");
s = s.replace(/<br>/g, "\n");
return s; 
}