出现错误：无法读取未定义的属性'addEvenetListener'

Question

我正在尝试在测验网站中实施夜间模式。

当我加载页面时，它说无法读取未定义的属性'addEventListener'。我尝试如下

HTML

<button class="js--toggle-lights">Change Theme</button>

脚本

var d = document.documentElement,
    t = document.querySelectorAll(".js--toggle-lights")[0],
    m = localStorage.getItem("nightmode");

if(m == "true") {
    d.classList.add("night-mode");
}

t.addEventListener("click", function(){
    if(d.classList.contains("night-mode")) {
        d.classList.remove("night-mode");
        localStorage.setItem("nightmode", "false");
    }else {
        d.classList.add("night-mode");
        localStorage.setItem("nightmode", "true");
    }
});

样式

.js--toggle-lights {
      border: 1px solid currentColor;
      color: inherit;
 }
 .night-mode {
      background: #000;
      color: #fff;
  }