document.write()使阻止默认行为失效了

 var ul = document.createElement("ul");
      ul.style.display = "none";
      document.body.appendChild(ul);
      var arr = ["vue", "react", "angular"];
      for (var i = 0; i < arr.length; i++) {
        var li = document.createElement("li");
        7;
        li.innerText = arr[i];
        ul.appendChild(li);
        setStyle(li, {
          padding: "10px 0",
          margin: 0,
        });
      }
      window.oncontextmenu = function () {
        var e = window.event;
        var x = e.pageX;
        var y = e.pageY;
        setStyle(ul, {
          width: "100px",
          display: "block",
          listStyle: "none",
          padding: 0,
          margin: 0,
          border: "1px solid #ccc",
          position: "absolute",
          left: x + 20 + "px",
          top: y + 20 + "px",
        });
        return false;
      };

      document.onclick = function () {
        console.log(ul)
        ul.style.display = "none";
      };
      ul.onmouseover = function () {
        for (i = 0; i < ul.children.length; i++) {
          ul.children[i].style.backgroundColor = "";
        }
        var e = window.event;
        var target = e.target || e.srcElement;
        if (target.tagName === "LI") {
          target.style.backgroundColor = "#ccc";
        } 
      };
      ul.onclick = function () {
        var e = window.event;
        var target = e.target || e.srcElement;
        if (target.tagName === "LI") {
          document.write("你选择了" + target.innerText);
        }
      };

```