Whether it is on a glass windshield or a glass table, you can repair a crack with a resin-based glass repair kit. It is important to repair cracked glass as soon as it happens to prevent the crack from expanding outwards, causing permanent damage to a glass surface.
Spray a moderate amount of glass cleaner onto the glass' surface. Wipe away streaks and dirt from the glass with newspaper. Allow the glass to completely air dry before proceeding to repair the crack.
Use a resin-based syringe-style repair kit. Remove the hole from the adhesive disc that came with the kit. Peel the disc backing off and stick the disc onto the cracked part of the glass. Position the crack in the disc's hole, pointing the disc's tab upward.
Peel off the disc's topside backing and press on the syringe's pedestal (its top part), making sure to align its tabs at the top. Uncap the syringe from the kit's contents and insert it inside the pedestal. Twist the pedestal until the syringe secures in place.
Pull up on the syringe plunger to remove all air pockets from the crack. Hold the syringe in this position for a few seconds and release. The force of the syringe should inject the repair compound into the crack. Expect to plunge at least 10 to 15 times.
Set the glass outside or in an area that is well-ventilated for 30 minutes so that the compound can set. Clean up any excess compound left on glass with a damp towel.