无法阅读属性＆＃39; style＆＃39;在HTMLImageElement中未定义。<anonymous>

Question

每次尝试访问.style属性时出现此问题。每次我尝试在javascript中使用.style修改CSS属性时都会发生这种情况。

  

code.js：9 Uncaught TypeError：无法读取属性＆＃39; style＆＃39;的   未定义       在HTMLImageElement。

for(var i = 0; i<description.length;i++) {
  image[i].addEventListener("mouseover", function() {
    description[i].style.visibility = visible;
    description[i].style.opacity = 0;
    var last = +new Date();
    var tick = function() {
      description[i].style.opacity = +description[i].style.opacity + (new Date() - last)/700;
      last = +new Date();

      if (+description[i].style.opacity < 1) {
        (window.requestAnimationFrame && requestAnimationFrame(tick)) || setTimeout(tick, 16);
      }
    };

    tick();
  });
}