allow filtering

[matkoniecz]

especially in regions with high density of opening hours one may prefer to ignore some classes of objects.

Would it be welcomed to make PR that would allow to specify in URL parameter allowing to add filter to the overpass query?

[matkoniecz]

For example in http://openingh.openstreetmap.de/?zoom=16&lat=50.07983&lon=19.88411&layers=B0T&tags=opening_hours somebody started marking parkings with 24/7.

It is not really incorrect so tag removal is not a solution. On the other hand this data is completely useless (parkings may be safely assumed to be always open, so only opening_hours!=24/7 are really useful).

[ypid]

Do as you please. I am currently not actively working on the map. I thought the map could one day be redone basing it on some other better maintained map.

[matkoniecz]

I thought the map could one day be redone

In any case - at least for me it works very well and thanks for your work on it!