How do I keep the neighbors weeds from my grass via chain link fence?

That’s a hard one, because one of the purposes of the wind is to spread seeds and pollen. If you cannot immediately replace the fence, you can weave plastic webbing through the chain link. Or you can attach thick plastic or canvas drop cloths to the fence. That won’t stop the wind and insects from overhead or down the street. Best wishes!

Dig a small trench along the fence on your side just below the grass. Cover with some plastic or landscape fabric in the trench. Fill with any kind of gravel. This will prevent grass and weeds from crossing over.

Kill off by pouring vinegar along base of fence.

William’s idea is great — I’m going to try that myself.

1. Edging.
2. Mulching with big rocks.
3. Spraying herbicides.
4. Installing weed barriers.
5. Building hedges barriers.
6. Fortifying Lawn.
7. Pulling the weeds with bare hands.

This post might be able to help you out! https://www.a1fenceinc.com/blog/2014/11/preventing-grass-and-weeds-under-your-chain-link-fence/