// ====================================================================
//       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.albionresarch.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.
// ====================================================================

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);
			}
		}
	}
  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++;
		}
	}
  return plaintext;
}

function getURLArgVal(argname,url)
{
  var u=url;
  var p=u.indexOf(argname+'=');
  if (p>=0){
    var pp=u.indexOf('&',p);
    u=u.substring(p+argname.length+1,pp>=0?pp:u.length);
  }
  else u='';
  return u;
}

function replaceURLArgVal(argname,argval,url)
{
  var u=url;
  var p=u.indexOf(argname+'=');
  if (p>=0){
    var pp=u.indexOf('&',p);
    u=u.substring(0,p)+(pp>=0?u.substring(pp+1,u.length):'');
  }
  return u+(((u.length<=0) || (u.charAt(u.length-1)=='&'))?'':'&')+argname+'='+argval;
}

function removeURLArgVal(argname,url)
{
  var u=url;
  var p=u.indexOf(argname+'=');
  if (p>=0){
    var pp=u.indexOf('&',p);
    u=u.substring(0,p)+(pp>=0?u.substring(pp+1,u.length):'');
  }
  return u;
}

function openURL(url,target,promptBeforeMsg,promptBeforeDef,promptCond)
{
  var ok=true;
  var pr='';
  var pc=promptCond;
  if (promptBeforeMsg){
    if (promptBeforeDef=='confirm') ok=confirm(promptBeforeMsg)
    else{
      pr=prompt(promptBeforeMsg,promptBeforeDef);
      if (!pc) pc='>0';
      ok=(pr!=null) && (eval('pr'+pc));
    }
  }
  if (ok){  
    var d=new Date();
    var u=replaceURLArgVal('ts',d.getTime(),url+pr);
    if (u.indexOf('lang=')<0) u=replaceURLArgVal('lang',lang,u);
    window.open(u,target?target:'_self');
  }
}