Catching Tabs in TextArea

2020-07-09 03:01发布

站内问答 / JavaScript
1980 3 6

Does anyone know a cross-browser, reliable solution for catching presses of the tab-key in a textarea field, and replacing (in the correct position) 4 spaces? The textarea is being used to input an essay, and needs this feature.

Note: I tried using FCKEditor, among others, which did not catch tabs and had a bunch of features I didn't need. I want a simple solution just for catching tabs.

3条回答
别忘想泡老子
2楼-- · 2020-07-09 03:26

Is there some reason you can't just replace the tabs after the editing is done? I've played around quite a bit with replacing text while typing in a textarea, and found it to be... impractical at best.

查看更多
0人赞 添加讨论(0) 举报
Root（大扎）
3楼-- · 2020-07-09 03:28

I didn't test extensively, but this seems to work:

(I found the "insertAtCursor" function at http://alexking.org/blog/2003/06/02/inserting-at-the-cursor-using-javascript#comment-3817)

<textarea id="text-area" rows="20" cols="100"></textarea>

<script>
document.getElementById("text-area").onkeydown = function(e) {
  if (!e && event.keyCode == 9)
  {
    event.returnValue = false;
    insertAtCursor(document.getElementById("text-area"), "    ");
  }
  else if (e.keyCode == 9)
  {
    e.preventDefault();
    insertAtCursor(document.getElementById("text-area"), "    ");
  }
};

//http://alexking.org/blog/2003/06/02/inserting-at-the-cursor-using-javascript#comment-3817
function insertAtCursor(myField, myValue) {
  //IE support
  if (document.selection) {
    var temp;
    myField.focus();
    sel = document.selection.createRange();
    temp = sel.text.length;
    sel.text = myValue;
    if (myValue.length == 0) {
      sel.moveStart('character', myValue.length);
      sel.moveEnd('character', myValue.length);
    } else {
      sel.moveStart('character', -myValue.length + temp);
    }
    sel.select();
  }
  //MOZILLA/NETSCAPE support
  else if (myField.selectionStart || myField.selectionStart == '0') {
    var startPos = myField.selectionStart;
    var endPos = myField.selectionEnd;
    myField.value = myField.value.substring(0, startPos) + myValue + myField.value.substring(endPos, myField.value.length);
    myField.selectionStart = startPos + myValue.length;
    myField.selectionEnd = startPos + myValue.length;
  } else {
    myField.value += myValue;
  }
}
</script>

EDIT: Modified the script so it doesn't use jQuery.

查看更多
0人赞 添加讨论(0) 举报
Emotional °昔
4楼-- · 2020-07-09 03:42 
<html>
<head>
    <script type="text/javascript">

        function keyHandler(e) {
            var TABKEY = 9;
            var backSlash = 8;
            var code = e.keyCode ? e.keyCode : e.charCode ? e.charCode : e.which;
            if(code == TABKEY && !e.shiftKey && !e.ctrlKey && !e.altKey) {
            var val = document.getElementById("t1");
                val.value=(val.value).substring(0,getCaret(val)) + "    " + (val.value).substring(getCaret(val));
                //document.getElementById("t1").value += "    ";

                if(e.preventDefault) {
                    e.preventDefault();
                } else {
                    e.returnValue = false;
                }
                val.focus(); 
                return false;
            }
            if(code == backSlash) {
                var val = document.getElementById("t1");
                val.value=(val.value).substring(0,getCaret(val)-4) + (val.value).substring(getCaret(val));
                if(e.preventDefault) {
                    e.preventDefault();
                } else {
                    e.returnValue = false;
                }
                return false;
            }

        }

        function getCaret(el) { 
          if (el.selectionStart) { 
            return el.selectionStart; 
          } else if (document.selection) { 
            el.focus(); 

            var r = document.selection.createRange(); 
            if (r == null) { 
              return 0; 
            } 

            var re = el.createTextRange(), 
                rc = re.duplicate(); 
            re.moveToBookmark(r.getBookmark()); 
            rc.setEndPoint('EndToStart', re); 

            return rc.text.length; 
          }  
          return 0; 
        }
    </script>
</head>
<body>
 <textarea id="t1" onkeydown="javascript:keyHandler(event)"></textarea>

</body>
</hrml>
查看更多
0人赞 添加讨论(0) 举报
登录 后发表回答
相关问题
查看全部
相关文章
查看全部
收藏的人(6)