《大話設計模式》第1章:用JavaScript語言描述(三)

第一章1.9節的原始碼用JS的原型繼承重寫：

function Operation() {}Operation.prototype.numA = 0;Operation.prototype.numB = 0;Operation.prototype.GetResult = function() {    var result = 0.00;    return result;}

function OperationAdd() {}OperationAdd.prototype = new Operation();OperationAdd.prototype.GetResult = function() {    var result = 0.00;    result = numA + numB;    return result;}function OperationSub() {}OperationSub.prototype = new Operation();OperationSub.prototype.GetResult = function() {    var result = 0.00;    result = numA - numB;    return result;}function OperationMul() {}OperationMul.prototype = new Operation();OperationMul.prototype.GetResult = function() {    var result = 0.00;    result = numA * numB;    return result;}function OperationDiv() {}OperationDiv.prototype = new Operation();OperationDiv.prototype.GetResult = function() {    var result = 0.00;    if(numB == 0)    {        alert('除數不能為0。');        return false;            }    result = numA / numB;    return result;}