// ====================================================================
//       URLEncode and URLDecode functions
//
// Copyright Albion Research Ltd. 2002
// http://www.albionresearch.com/
//
// You may copy these functions providing that 
// (a) you leave this copyright notice intact, and 
// (b) if you use these functions on a publicly accessible
//     web site you include a credit somewhere on the web site 
//     with a link back to http://www.albionresearch.com/
//
// If you find or fix any bugs, please let us know at albionresearch.com
//
// SpecialThanks to Neelesh Thakur for being the first to
// report a bug in URLDecode() - now fixed 2003-02-19.
// And thanks to everyone else who has provided comments and suggestions.
// ====================================================================
function URLEncode(plaintext) {
    // The Javascript escape and unescape functions do not correspond
    // with what browsers actually do...
    var SAFECHARS = "0123456789" + 				// Numeric
				            "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + // Alphabetic
				            "abcdefghijklmnopqrstuvwxyz" +
				            "-_.!~*'()"; 				// RFC2396 Mark characters
    var HEX = "0123456789ABCDEF";
    var encoded = "";
    for (var i = 0; i < plaintext.length; i++) {
        var ch = plaintext.charAt(i);
        if (ch == " ") {
            encoded += "+"; 			// x-www-urlencoded, rather than %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);
            }
        }
    } // for

    return encoded;
};

function URLDecode(encoded) {
    // Replace + with ' '
    // Replace %xx with equivalent character
    // Put [ERROR] in output if %xx is invalid.
    var HEXCHARS = "0123456789ABCDEFabcdef";
    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++;
        }
    } // while
    return plaintext;
};
// -->


function Underscore(plaintext) {
    return plaintext.replace(" ", "_");
}