In a bowl, combine the flour, baking soda, and salt.
Set aside.
In a large bowl, cream the margarine with a large wooden spoon.
Add the brown and granulated sugars, continuing to cream until well blended.
Beat in the eggs, one at a time, and the vanilla.
Mix in the dry ingredients, using your hands to blend them well.
Gently stir in the semisweet chocolate chips.
Drop heaping tablespoonfuls of dough onto parchment-lined cookie sheets.
Bake for about 8 minutes.
Be careful not to overcook.
Place the baking sheet on a rack to allow air circulation under the cookies as they cool, or slide parchment paper, with the cookies still in place, onto racks to cool.
Once completely cool, store the cookies tightly covered.