Game.prototype.restart = function () { 
this.clearLocalStorage(); 
this.timer = setTimeout (function() { 
this.clearBoard(); 
}, 0); 
};

uncaught typeError：undefined is not a function

Game.prototype.restart = function() { 
this.clearLocalStorage(); 
var self = this; 
this.timer = setTimeout(function(){ 
self.clearBoard(); }, 0); 
}; //改变了作用的对象 

Game.prototype.restart = function () { 
this.clearLocalStorage(); 
this.timer = setTimeout(this.reset.bind(this)), 
}; 
Game.prototype.reset = function() { 
this.clearBoard(); 
};

for (var i=0; i<10;i++){ 
/* */ 
} 
console.log(i); //并不会提示 未定义，结果是10 

var theThing = null; 
var replaceThing = function() { 
var priorThing = theThing; 
var unused = function() { 
if (priorThing) { 
console.log(‘hi'); 
}; 
}; 
theThing = { 
longStr: new Array(1000000).join(‘*'), 
someMethod: function () { 
console.log(someMessage); 
} 
} 
setInterval(replaceThing, 1000);

console.log(false == ‘0'); // true 
console.log(null == undefinded); //true 
console.log(” \t\r\n” == 0);