function Utils() { if(typeof Utils.initialized == "undefined"){ console.log("prototype init"); Utils.prototype.utilsFunc1 = function () { console.log("utilsFunc1"); }; Utils.prototype.utilsFunc2 = function () { console.log("utilsFunc2"); }; } Utils.initialized =true; } var instance1 = new Utils(); instance1.utilsFunc1(); var instance2 = new Utils(); instance2.utilsFunc1();
“prototype init ” 只打印一次