function addQueryString( url, params )
	{
		var queryString = [];

		if ( !params )
			return url;
		else
		{
			for ( var i in params )
				queryString.push( i + "=" + encodeURIComponent( params[ i ] ) );
		}

		return url + ( ( url.indexOf( "?" ) != -1 ) ? "&" : "?" ) + queryString.join( "&" );
	}
Adds (additional) arguments to given url.

@param {String}
           url The url.
@param {Object}
           params Additional parameters.