Strawberry jam with no preservatives

Strawberry jam with no preservatives......
Strawberry jam
Ingredients
3 cups strawberries sliced
2 cups sugar
1/2 tsp salt

Method
Mix all the ingredients and keep it on medium flame, stirring it constantly till the juices reduces and to  test take 1/2 cup water and pour a drop of jam in the water. If it spreads then the jam is not ready. Once ready the jelly droplet will retain its shape once dropped in the water. Once done cool it and store it in a jar....