[javascript] javascript的html转义,特殊字符转义

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, "'");   
    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(/&gt;/g, "&");   
    s = s.replace(/&lt;/g, "<");   
    s = s.replace(/&gt;/g, ">");   
    s = s.replace(/&nbsp;/g, " ");   
    s = s.replace(/'/g, "\'");   
    s = s.replace(/&quot;/g, "\"");   
    s = s.replace(/<br>/g, "\n");   
    return s;   
}