URLencode si URLdecode cu JavaScript

var str = "hello34ad#4"; 
alert(escape(str)); 
alert(unescape(str));

var str = 'http://www.yahoo.com'; 
alert(encodeURI(str)); 
alert(decodeURI(str));

function URLEncode(url){ //Function to encode URL. 
    // Functiile Javascript escape si unescape nu corespund  
    // cu ceea ce fac de fapt browserele... 
    var SAFECHARS = "0123456789" + // Numeric 
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + // Alphabetic 
    "abcdefghijklmnopqrstuvwxyz" + 
    "-_.!~*'()"; // RFC2396 Mark characters 
    var HEX = "0123456789ABCDEF";
 
    var plaintext = url; 
    var encoded = ""; 
    for (var i = 0; i < plaintext.length; i++ ) { 
        var ch = plaintext.charAt(i); 
        if (ch == " ") { 
            encoded += "+"; // x-www-urlencoded, mai degraba, decat %20 
        } else if (SAFECHARS.indexOf(ch) != -1) { 
            encoded += ch; 
        } else { 
            var charCode = ch.charCodeAt(0); 
            if (charCode > 255) { 
                alert( "Unicode Character '"  + ch 
                + "' cannot be encoded using standard URL encoding.\n"  
                + "(URL encoding only supports 8-bit characters.)\n" 
                + "A space (+) will be substituted." ); 
                encoded += "+"; 
            } else { 
                encoded += "%"; 
                encoded += HEX.charAt((charCode >> 4) & 0xF); 
                encoded += HEX.charAt(charCode & 0xF); 
            } 
        } 
    }
    return encoded; 
}
 
function URLDecode(url){ //functia decode URL 
    // Inlocuieste + cu ' ' 
    // Inlocuieste %xx cu caracterul echivalent 
    // Trece [ERROR] ca iesire daca %xx nu este valid. 
    var HEXCHARS = "0123456789ABCDEFabcdef";  
    var encoded = url; 
    var plaintext = ""; 
    var i = 0; 
    while (i < encoded.length) { 
        var ch = encoded.charAt(i); 
        if (ch == "+") { 
            plaintext += " "; 
            i++; 
        } else if (ch == "%") { 
            if (i < (encoded.length-2)  
                && HEXCHARS.indexOf(encoded.charAt(i+1)) != -1  
                && HEXCHARS.indexOf(encoded.charAt(i+2)) != -1 ) { 
                plaintext += unescape( encoded.substr(i,3) ); 
                i += 3; 
            } else { 
                alert( 'Bad escape combination near ...' 
                + encoded.substr(i) ); 
                plaintext += "%[ERROR]"; 
                i++; 
            } 
        } else { 
            plaintext += ch; 
            i++; 
        } 
    } // cat timp returneaza text simplu; 
}