我试图从我的构造函数中访问一个属性,但我继续得到" Uncaught TypeError:无法读取属性' length'未定义的。"我想要访问的属性是数组this.possibleX。请指教。谢谢!
var Item = function() {
this.x = this.positionX();
this.y = this.positionY();
this.sprite = this.spritePic()
this.possibleX = [0,100,200,300,400];
this.possibleY = [80,160,240,320];
this.spriteOptions = ['images/Rock.png','images/Rock.png','images/Rock.png','images/Heart.png','images/Gem Blue.png', 'images/Gem Green.png', 'images/Gem Orange.png'];
}
Item.prototype.positionX = function() {
var startX = this.possibleX[Math.round(Math.random() * this.possibleX.length)];
return startX;
}
var item = new Item();
答案 0 :(得分:1)
var Item = function() {
this.x = this.positionX();
注意你是如何首先调用该函数然后定义this.possibleX = [0,100,200,300,400];
的。您需要反转此订单。