下面的自己在绑定一个键盘事件就行了
/* ==== right arrow ==== */
this.arR.onclick = this.arR.ondblclick = function() {
if (this.parent.view < this.parent.NF - 1)
this.parent.calc(1);
}
/* ==== Left arrow ==== */
this.arL.onclick = this.arL.ondblclick = function() {
if (this.parent.view > 0)
this.parent.calc(-1);
}