javascript - How to prevent input to a textarea after a certain character count is reached? - Stack Overflow

Using the below code, any input exceeding the specified maximum is removed. But this creates an effect where a character is typed and then immediately removed. I would prefer to simply prevent characters from being inputted.

<textarea  id="textarea" onKeyDown="limitText()" onKeyUp="limitText()">
</textarea> 
<span name="charcount_text" id="charcount_text"></span>

  <script type="text/javascript">
    function limitText() {
      var count = document.getElementById('textarea').value.length;
      var remaining = 4000 - count;
      if(remaining <= 0) {
        document.getElementById('charcount_text').innerHTML = '4000 character limit reached.' ;
        document.getElementById('textarea').value = document.getElementById('textarea').value.substring(0, 4000);
      } else if(remaining <= 50) {
        document.getElementById('charcount_text').innerHTML = '4000 character limit, ' + remaining  + ' remaining.';
      } else {
        document.getElementById('charcount_text').innerHTML = '';
      }
    }
  </script>

Using the below code, any input exceeding the specified maximum is removed. But this creates an effect where a character is typed and then immediately removed. I would prefer to simply prevent characters from being inputted.

<textarea  id="textarea" onKeyDown="limitText()" onKeyUp="limitText()">
</textarea> 
<span name="charcount_text" id="charcount_text"></span>

  <script type="text/javascript">
    function limitText() {
      var count = document.getElementById('textarea').value.length;
      var remaining = 4000 - count;
      if(remaining <= 0) {
        document.getElementById('charcount_text').innerHTML = '4000 character limit reached.' ;
        document.getElementById('textarea').value = document.getElementById('textarea').value.substring(0, 4000);
      } else if(remaining <= 50) {
        document.getElementById('charcount_text').innerHTML = '4000 character limit, ' + remaining  + ' remaining.';
      } else {
        document.getElementById('charcount_text').innerHTML = '';
      }
    }
  </script>

• javascript
• html

Share Improve this question Follow asked May 6, 2015 at 21:40 ab11ab11 20.1k4444 gold badges123123 silver badges214214 bronze badges 3

• 2 possible duplicate of textarea character limit – Paul Roub Commented May 6, 2015 at 21:44
• Also possible duplicate of stackoverflow./questions/3578678/… – Leo Farmer Commented May 6, 2015 at 21:46
• possible duplicate of Prevent user from writing more than N characters in a textarea using Prototype event observers – Alex Pan Commented May 6, 2015 at 21:47

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2 Answers 2

Sorted by: Reset to default 10

Use the maxlength attribute:

<textarea  id="textarea" maxlength="4000" onkeyup="limitText()"></textarea>

function limitText() {
  var ta= document.getElementById('textarea'),
      count= ta.value.length,
      ml= ta.maxLength,
      remaining= ml - count,
      cc= document.getElementById('charcount_text');

  if(remaining <= 0) {
    cc.innerHTML = ml+' character limit reached.' ;
  } else if(remaining <= 50) {
    cc.innerHTML = ml+' character limit, ' + remaining  + ' remaining.';
  } else {
    cc.innerHTML = '';
  }
}

Fiddle

Try this

$.fn.lenghtLimit = function(numLimit) {
  var currentEle = $(this);

  function main() {
    var getCurrentVal = currentEle.val();
    if (getCurrentVal.length > numLimit) {
        currentEle.val(getCurrentVal.substring(0, numLimit));
    }
  }
  $(document).on("keyup", currentEle, main);
}

// call method here with number limit
$("#numberInput").lenghtLimit(10);

You can limit any input or textarea value length using this https://jsfiddle/akalankaimesh/7hkagewh/