如何从文本区域中突出显示的文本中获取邻居字符？

user5137948 发表于 Dev

用户名

这将返回突出显示的文本：

function getSelection(elem) {
    var selectedText;

    if (document.selection != undefined) { // IE
        elem.focus();
        var sel = document.selection.createRange();
        selectedText = sel.text;
    } else if (elem.selectionStart != undefined) { // Firefox
        var startPos = elem.selectionStart;
        var endPos   = elem.selectionEnd;
        selectedText = elem.value.substring(startPos, endPos)
    }
    return selectedText;
}

$(document).on('mousedown', 'button', function(e) {
  var selection =  getSelection( $('#txtarea').get(0) );
  alert(selection);
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<textarea id="txtarea">this is a test</textarea>
<button>highlighted text</button>

现在，我需要从选中/突出显示的文本中选择相邻字符。例如，如果his is a t选中，那么我需要同时获得t（L）和e（R）字符。我怎样才能做到这一点？

试试这个

function GetSelection() {
  var selection = "";

  var textarea = document.getElementById("myArea");
  if ('selectionStart' in textarea) {
    // check whether some text is selected in the textarea
    if (textarea.selectionStart != textarea.selectionEnd) {
      selection = textarea.value.substring(textarea.selectionStart - 1, textarea.selectionEnd + 1);
    }
  } else { // Internet Explorer before version 9
    // create a range from the current selection
    var textRange = document.selection.createRange();
    // check whether the selection is within the textarea
    var rangeParent = textRange.parentElement();
    if (rangeParent === textarea) {
      selection = textRange.text;

    }
  }

  if (selection == "") {
    alert("No text is selected.");
  } else {
    alert("The current selection is: " + selection);
  }
}

<body>
  <textarea id="myArea" spellcheck="false">Select some text within this field.</textarea>
  <button onclick="GetSelection ()">Get the current selection</button>
</body>

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