function testUndefinedBooleanCmp() { var t = true, f = false, x = []; for (var i = 0; i < 10; ++i) { x[0] = t == undefined; x[1] = t != undefined; x[2] = t === undefined; x[3] = t !== undefined; x[4] = t < undefined; x[5] = t > undefined; x[6] = t <= undefined; x[7] = t >= undefined; x[8] = f == undefined; x[9] = f != undefined; x[10] = f === undefined; x[11] = f !== undefined; x[12] = f < undefined; x[13] = f > undefined; x[14] = f <= undefined; x[15] = f >= undefined; } return x.join(","); } assertEq(testUndefinedBooleanCmp(), "false,true,false,true,false,false,false,false,false,true,false,true,false,false,false,false");