Input.GetMouseButton NEVER returns false

Ok, so heres my code:

if(Input.GetMouseButton(0)) {
            anim.SetBool("fireWeapon", true);
            fW = true;
        }else{
            anim.SetBool("fireWeapon", false);
            fW = false;
        }
        Debug.Log(string.Format("{0}", fW));

Initially, the debug returns false, as i havent pressed the left mouse button yet. But when I do press it it changes to true but never changes back. Veeeery confused.


Any help would be lovely ;3

Sorry lads, i fixed it. The problem was i didn’t check the box in the parameters menu, that little one next to the name.
What does that do? o.O