更新更容易：

使用时selectionStart，它与所有主要浏览器兼容。

document.getElementById('foobar').addEventListener('keyup', e => {
  console.log('Caret at: ', e.target.selectionStart)
})
<input id="foobar" />

更新：仅当未定义类型或type="text"在输入上时，此方法才有效。

旧答案：

找到了这个解决方案。不是基于jquery的，但是将其集成到jquery中没有问题：

/*
** Returns the caret (cursor) position of the specified text field (oField).
** Return value range is 0-oField.value.length.
*/
function doGetCaretPosition (oField) {

  // Initialize
  var iCaretPos = 0;

  // IE Support
  if (document.selection) {

    // Set focus on the element
    oField.focus();

    // To get cursor position, get empty selection range
    var oSel = document.selection.createRange();

    // Move selection start to 0 position
    oSel.moveStart('character', -oField.value.length);

    // The caret position is selection length
    iCaretPos = oSel.text.length;
  }

  // Firefox support
  else if (oField.selectionStart || oField.selectionStart == '0')
    iCaretPos = oField.selectionDirection=='backward' ? oField.selectionStart : oField.selectionEnd;

  // Return results
  return iCaretPos;
}