Is it illegal to install small LED screens in residential windows?

First, make sure whether you install it outside the window or inside the window. The window is suspected of affecting the overall environment of the community, and the external wall belongs to the public part, so the property will definitely not let you install it. Besides, you installed an advertisement. Property is not allowed. If you put it in the window, it has nothing to do with the property in principle, but it is best to say hello to the property.