function getParameter ( queryString, parameterName ) {
	   // Add "=" to the parameter name (i.e. parameterName=value)
	   var parameterName = parameterName + "=";
	   if ( queryString.length > 0 ) {
	      // Find the beginning of the string
	      begin = queryString.indexOf ( parameterName );
	      // If the parameter name is not found, skip it, otherwise return the value
	      if ( begin != -1 ) {
	         // Add the length (integer) to the beginning
	         begin += parameterName.length;
	         // Multiple parameters are separated by the "&" sign
	         end = queryString.indexOf ( "&" , begin );
	      if ( end == -1 ) {
	         end = queryString.length
	      }
	      // Return the string
	      return unescape ( queryString.substring ( begin, end ) );
	   }
	   // Return "null" if no parameter has been found
	   return "null";
	   }
	}