修改上下左右键
  
  

  
上：
  

  
  

  
下：
  

  
  

  
左：
  

  
  

  
右：
  

  
  

  

  
 
 

var up, down, left, right;
var up1, down1, left1, right1;
var obj = document.getElementById("img");
obj.left = 0;
obj.top = 0;
//通过设置四个不同参数来进行判断
function myFunction(str) {
 var Key = window.event.keyCode;
 //当str=设置的参数时把key赋值给up1
 if (str == "up") {
 up1 = Key;
 }
 if (str == "down") {
 down1 = Key;
 }
 if (str == "left") {
 left1 = Key;
 }
 if (str == "right") {
 right1 = Key;
 }
}
//确定函数事件
function confirm() {
 //把up1赋值给up
 up = up1;
 down = down1;
 left = left1;
 right = right1;
 alert("您设置的热键键值为:" + up + ";" + down + ";" + left + ";" + right);
 fkey();
}
function fkey() {
 console.log(event.keyCode);
 var Key = window.event.keyCode;
 //获取你自定义的键和键盘上下左右键都可以用
 if (Key == 37 || Key == parseInt(left)) {
 //左
 obj.left -= 80;
 }
 if (Key == 38 || Key == parseInt(up)) {
 //上
 obj.top -= 80;
 }
 if (Key == 39 || Key == parseInt(right)) {
 //右
 obj.left += 80;
 }
 if (Key == 40 || Key == parseInt(down)) {
 //下
 obj.top += 80;
 }
 obj.style.left = obj.left + "px", obj.style.top = obj.top + "px";
}
document.onkeydown = fkey;