小编Jeh*_*yun的帖子

function arithFunc() {
    var n = 0;
    return {
        plusOP: function() {
            return n++;
        },
        minusOP: function() {
            return n--;
        }

    };
}

var aTest = arithFunc(),
    bTest = arithFunc();

document.getElementById("demo").innerHTML = aTest.plusOP();
document.getElementById("demo").innerHTML = aTest.plusOP();
document.getElementById("demo").innerHTML = bTest.minusOP();
document.getElementById("demo").innerHTML = aTest.plusOP();
document.getElementById("demo").innerHTML = bTest.minusOP();
document.getElementById("demo").innerHTML = aTest.plusOP();

<p id="demo"></p>