michael@0: function f(x) {
michael@0:     for (var i=0; i<50; i++) {
michael@0:         assertEq(x == null, false);
michael@0:         assertEq(x == undefined, false);
michael@0:         assertEq(x != null, true);
michael@0:         assertEq(x != undefined, true);
michael@0:         assertEq(x === null, false);
michael@0:         assertEq(x === undefined, false);
michael@0:         assertEq(x !== null, true);
michael@0:         assertEq(x !== undefined, true);
michael@0:         assertEq(x < null, false);
michael@0:         assertEq(x >= null, true);
michael@0:     }
michael@0: }
michael@0: f(10);
michael@0: f(0);