a stupid question

me being new to the trucking industry. I always thought that the real Low visors looked kind of stupid. but after getting into a truck with one I found out they are pretty useful blocking sunlight in your eyes and not just for looks. I want to get one for my truck but I don't want to pay $350 to $450 for a company truck. plus the ones for international don't look like they would work very well. now here's the stupid question. do they make a window tinting or a sticker type visor that will stick to the inside of the windshield that will do the same thing? or is that getting into the realm of no illegal stickers for visual obstructions on the windshield?

 

So lets say I can find some of that rubbery film like they use to write your mileage on at jiffy lube and stick it to the inside of the windshield but its all clear but tinted. If I stuck that onto the inside of the windshield along the top and it came down to where a regular visor would, that would be considered illegal? If that's the case then how can regular visors be legal since they totally obstruct the view? Or is it one of those weird laws that make no since. Like in Washington State where it is perfectly fine to not have a windshield but if you have no windshield wipers then your breaking the law.