What Is The Best Way To Limit The Amount Of Text That Can Be Entered Into A 'textarea'?

What is the best way to limit the amount of text that a user can enter into a 'textarea' field on a web page? The application in question is ASP .NET, but a platform agnostic answe

Solution 1:

functionlimit(element, max_chars)
{
    if(element.value.length > max_chars)
        element.value = element.value.substr(0, max_chars);
}

As javascript, and...

<textareaonkeyup="javascript:limit(this, 80)"></textarea>

As XHTML. Replace 80 with your desired limit. This is how I do it anyway.

Note that this will prevent the user from typing past the limit in the textbox, however the user could still bypass this using javascript of their own. To make sure, you must also check with your server side language.

Solution 2:

use a RegularExpressionValidator Control in ASP.Net to validate number of character along with with usual validation

Solution 3:

The most user-friendly idea seems to me a solution like the Twitter-one. Provide a visual indication that the user has crossed the maximum but don't limit him in typing.

Whatever Javascript you use, you will still have to validate at the server end. Users with Javascript disabled will otherwise be able to circumvent your limit.

Solution 4:

As Javache said, you'll still have to check server side. We've been using the jQuery validator plugin which has support for Max lengths amongst tones of other stuff...

Solution 5:

I use this, where the limit is a must. It also provides the user with the number of characters left.

functionCountLength(vControl)
    {
        var strValue = vControl.value;
        var vMax = 480;
        var vLeft = vMax - strValue.length;
        if (vLeft < 0)
        {
            vLeft = 0;
        }
        var vMessage = returnObjById('TextCounter');
        if (document.all)
        {
            vMessage.innerText = vLeft + ' characters remaining.';
        }
        else
        {   
            vMessage.textContent = vLeft + ' characters remaining.';
        }
        if (vLeft == 0)
        {
            vControl.value = vControl.value.substring(0, vMax);
        }
    }