_isSafari = function ()
{
	return navigator.userAgent.indexOf('Safari') !== -1 &&
		navigator.userAgent.indexOf('Chrome') === -1 &&
		navigator.userAgent.indexOf('Opera') === -1;
}
Safari's data: support for creating and downloading files is really poor, so
various options need to be disabled in it. See
https://bugs.webkit.org/show_bug.cgi?id=102914

@return {Boolean} `true` if Safari