使用Javascript在textarea中的光标处插入文本

function insertTextAtCursor(text) {
  var textarea = document.getElementById("myTextarea");
  var startPos = textarea.selectionStart;
  var endPos = textarea.selectionEnd;
  var value = textarea.value;
  
  var beforeText = value.substring(0, startPos);
  var afterText = value.substring(endPos, value.length);
  
  var newValue = beforeText + text + afterText;
  
  textarea.value = newValue;
  textarea.selectionStart = textarea.selectionEnd = startPos + text.length;
}