Contenteditable光标最终方案

拿到光标

function getcaretposition() {
    return window.getSelection().anchorOffset;
}

设置光标

function setcaretposition(t) {
    window.getSelection().collapse(window.getSelection().anchorNode, t);
}

事件

    editor.onkeypress = (e) => { //特别神奇, onpress对中文兼容是完美的. 为什么? 我不禁低头问大地.
      let cp = getcaretposition();
      dom.value = doing(editor); //处理每键
      save.value = savefile(editor); //这个是save的做法.
      setcaretposition(cp);
    }