Undo hover from JS

I have an element which changes the cursor, this with: hover

I want to be able to undo that change from javascript but keep the hover running when I move the cursor again.

.con_inf .inside:hover {
          width: 50%;
          left: 0;
          top: 0;
          border-radius: 0;
          height: 100%;
          background: white;
        }