javascript - 查找动态创建的div

Question

我想更改动态创建的 div但我无法让它工作它不断创建新的 div

var div = document.getElementById('windowx');
var btn;
var doc = content.document

if (div)
{
  div = document.getElementById('windowx')
  div.innerHTML = "something new"
}
else
{
  doc = content.document
  div = doc.body.appendChild(doc.createElement("div"))
  div.setAttribute("id", "windowx")
  div.setAttribute("style",
    "position: fixed; top: 100px; left: 100px; width: 20em;"
    + "border: 2px outset orange; background-color: cornsilk;"
    )
  btn = div.appendChild(doc.createElement("button"))
  btn.setAttribute("style", "position: absolute; bottom: 1ex; right: 1ex;")
  btn.setAttribute("onclick", "document.body.removeChild(this.parentNode)")
  btn.appendChild(doc.createTextNode("Zamknij"))
}

Answer 1

现在很明显它是针对 Firefox 插件的:

document.getElementById 将在浏览器 UI 中搜索该元素，而不是网页。但稍后您将该元素添加到页面。因此，您必须在页面中搜索该元素:

var div = content.document.getElementById('windowx');

此外，您还进行了一些不必要的方法调用。这是代码的更简洁版本:

var doc = content.document,
    div = doc.getElementById('windowx'),
    btn;

if (div) {
  div.innerHTML = "something new"
}
else {
  div = doc.body.appendChild(doc.createElement("div"))
  div.setAttribute("id", "windowx")
  div.setAttribute("style",
    "position: fixed; top: 100px; left: 100px; width: 20em;"
    + "border: 2px outset orange; background-color: cornsilk;"
    )
  btn = div.appendChild(doc.createElement("button"))
  btn.setAttribute("style", "position: absolute; bottom: 1ex; right: 1ex;")
  btn.setAttribute("onclick", "document.body.removeChild(this.parentNode)")
  btn.appendChild(doc.createTextNode("Zamknij"))
}