Textarea counter of characters for maximum length limit

We can write one textarea counter to show our visitors the number of text or characters they entered inside the textarea. This counter will keep updating it self on entry or delete of any character inside the textarea. The counter shows decreasing value showing how many more characters can be entered or left to be entered. This way the visitor can keep track on its text entry based on the maximum length limit shown by the counter.

Every time as the text entered inside the textarea we can't send data to server so we will execute this program by using client side JavaScript.

Inside the Textarea we will use to event handlers, one is onKeyPress and other is onKeyDown. Both the event handlers will trigger one function in JavaScript. Inside this function we will check the length of the characters inside the textarea by using my_form.my_text.value.length with the maximum value set. If the length is less than the maximum set value then we can update the counter but if length is equal to or more than the set value then we can trim ( or remove ) the extra input from the string. We also can display one alert message if required.

demo of textarea counter

Here is the code

<html><head>
<title>(Type a title for your page here)</title>

<script language=JavaScript>
<!--
function check_length(my_form)
{
maxLen = 50; // max number of characters allowed
if (my_form.my_text.value.length >= maxLen) {
// Alert message if maximum limit is reached. 
// If required Alert can be removed. 
var msg = "You have reached your maximum limit of characters allowed";
alert(msg);
// Reached the Maximum length so trim the textarea
	my_form.my_text.value = my_form.my_text.value.substring(0, maxLen);
 }
else{ // Maximum length not reached so update the value of my_text counter
	my_form.text_num.value = maxLen - my_form.my_text.value.length;
}
}
//-->
</script>

</head>

<body>
<form name=my_form method=post>
<textarea onKeyPress=check_length(this.form); onKeyDown=check_length(this.form); 
 name=my_text rows=4 cols=30></textarea>
    <br>                               
<input size=1 value=50 name=text_num> Characters Left
</form>

</body>
</html>

Using JQuery:
Check this to develop same script by using JQuery keyup event.

Event Handling onMouseOver and onMouseOut

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Raman	23-04-2013
The code was right but need for button disabling with alert too

srilakshmi	19-12-2014
great job this is simple user understandable code,nd this helps me thanqx.

Akshit Saxena	25-08-2015
what if we press the "Backspace"... the code crashes in word count in that case... cannot be applied to major project.. can you please help it out...??

duna	30-05-2012
thank you, this worked well for me.

shana	10-07-2012
its very useful to all

Peter	19-07-2012
Thanks, u helped me so much :)

Cristian	04-10-2012
thanks a lot for the code!

Counting the characters dynamically inside a textarea and setting a limit