function zawartosc(x)
{
  var tag = document.getElementById(x);
  var odnosnik = tag.getElementsByTagName('div')[0];
  
  if (odnosnik.className == "simple")
  {
	  odnosnik.className = "extend";
	}
	else
	{
	  odnosnik.className = "simple";
  }
};



function mp3File(input) {
	  var keyStr = "ABCDEFGHIJKLMNOP" +
                "QRSTUVWXYZabcdef" +
                "ghijklmnopqrstuv" +
                "wxyz0123456789+/" +
                "=";

      var output = "";
      var chr1, chr2, chr3 = "";
      var enc1, enc2, enc3, enc4 = "";
      var i = 0;
  
      var base64test = /[^A-Za-z0-9\+\/\=]/g;
      if (base64test.exec(input)) {
         alert("There were invalid base64 characters in the input text.\n" +
               "Valid base64 characters are A-Z, a-z, 0-9, '+', '/',and '='\n" +
               "Expect errors in decoding.");
      }
      input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
  
      do {
         enc1 = keyStr.indexOf(input.charAt(i++));
         enc2 = keyStr.indexOf(input.charAt(i++));
         enc3 = keyStr.indexOf(input.charAt(i++));
         enc4 = keyStr.indexOf(input.charAt(i++));
  
         chr1 = (enc1 << 2) | (enc2 >> 4);
         chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
         chr3 = ((enc3 & 3) << 6) | enc4;
  
         output = output + String.fromCharCode(chr1);
  
         if (enc3 != 64) {
            output = output + String.fromCharCode(chr2);
         }
         if (enc4 != 64) {
            output = output + String.fromCharCode(chr3);
         }
  
         chr1 = chr2 = chr3 = "";
         enc1 = enc2 = enc3 = enc4 = "";
  
      } while (i < input.length);
  
      return unescape(output);
   };