JS编码解码函数

<script language="javascript" type="text/javascript">
var Url = {
 
    // public method for url encoding
    _encode : function (string) {
        return escape(this._utf8_encode(string));
    },
 
    // public method for url decoding
    _decode : function (string) {
        return this._utf8_decode(unescape(string));
    },
 
    // private method for UTF-8 encoding
    _utf8_encode : function (string) {
        string = string.replace(/\r\n/g,"\n");
        var utftext = "";
 
        for (var n = 0; n < string.length; n++) {
 
            var c = string.charCodeAt(n);
 
            if (c < 128) {
                utftext += String.fromCharCode(c);
            }
            else if((c > 127) && (c < 2048)) {
                utftext += String.fromCharCode((c >> 6) | 192);
                utftext += String.fromCharCode((c & 63) | 128);
            }
            else {
                utftext += String.fromCharCode((c >> 12) | 224);
                utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                utftext += String.fromCharCode((c & 63) | 128);
            }
 
        }
 
        return utftext;
    },
 
    // private method for UTF-8 decoding
    _utf8_decode : function (utftext) {
        var string = "";
        var i = 0;
        var c = c1 = c2 = 0;
 
        while ( i < utftext.length ) {
 
            c = utftext.charCodeAt(i);
 
            if (c < 128) {
                string += String.fromCharCode(c);
                i++;
            }
            else if((c > 191) && (c < 224)) {
                c2 = utftext.charCodeAt(i+1);
                string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
                i += 2;
            }
            else {
                c2 = utftext.charCodeAt(i+1);
                c3 = utftext.charCodeAt(i+2);
                string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
                i += 3;
            }
 
        }
 
        return string;
    }
}

var url = "google.cn/search?hl=zh-CN&source=hp&q=%E4%B8%AD%E6%96%87%E4%B9%B1%E7%A0%81%E7%BB%88%E6%9E%81%E8%A7%A3%E5%86%B3%E6%96%B9%E6%B3%95";
url = Url._decode(url);
document.write(url);
</script>