Unfortunately the answer is no you cannot repair cracks in a windscreen, but you can repair stone chips depending on the size and placement on the glass.

What we do is we use a British standard resin to fill the stone chip in the screen. 

We then apply pressure which sucks out any old dirt or water that’s still in the chip. 

After the chip repair your screen will not crack or split any further. 

It may be slightly still visible as they do not  disappear completely, 

but depending on how long the chip has been on the screen will determine on the outcome.