Javascript - 删除输入字段中的光标位置

Question

您将如何删除更改输入字段中光标位置的功能。因此，当用户键入时，他们总是会在最后键入。

Answer 1

您可能会遇到一些旧的浏览器限制，但这只是为了让您了解一下。
您需要处理 paste 和 keydown 事件。对于粘贴，您可能需要 Clipboard API 来拯救。废话不多说了:

function setRng(el, txt, from, to) {
  el.setSelectionRange(from + txt.length, to + txt.length);
}

function insVal(el, txt, from, to) {
  from = Math.max(0, from);
  to = to || from;
  el.value = el.value.substring(0, from) + txt + el.value.substring(to, el.value.length);
  setRng(el, txt, from, from);
}

function writeToEnd(ev) {
  var el = ev.target;
  var key = ev.keyCode;
  var isBackspace = key === 8;
  var isPaste = ev.type === "paste";
  var txt = isPaste ? (ev.clipboardData || window.clipboardData).getData('Text') : '';
  var fromOffset = isBackspace ? -1 : 0;
  
  if (txt && txt.length > 1 || isPaste || isBackspace) ev.preventDefault(); // Cause of some special input
  insVal(el, txt, el.value.length + fromOffset, el.value.length);
}

[...document.querySelectorAll('.writeToEnd')].forEach(el => {
  el.addEventListener('keydown', writeToEnd);
  el.addEventListener('paste', writeToEnd);
});

<input class="writeToEnd" type="text" value="input test"><br>
<textarea class="writeToEnd">textarea test</textarea><br>
(Test also COPY/PASTE using mouse and keyboard)

MDN Clipboard API ,
Stack Overflow get-clipboard-data