How can I block further input in textarea using maxlength

Question

I have a textarea that I want to block input on if the entered characters reaches a max-length.

I currently have a Jquery script for the textbox that calculates the characters entered and want to add something that will block input in the textarea once 150 characters are entered.

I have tried using max-length plugins in conjunction with my script but they don't seem to work. Help is appreciated.

CURRENT CODE

(function($) {
    $.fn.charCount = function(options){
        // default configuration properties
        var defaults = {    
            allowed: 150,       
            warning: 25,
            css: 'counter',
            counterElement: 'span',
            cssWarning: 'warning',
            cssExceeded: 'exceeded',
            counterText: '',
            container: undefined // New option, accepts a selector string
        }; 

        var options = $.extend(defaults, options); 

        function calculate(obj,$cont) {
              // $cont is the container, now passed in instead.
            var count = $(obj).val().length;
            var available = options.allowed - count;
            if(available <= options.warning && available >= 0){
                $cont.addClass(options.cssWarning);
            } else {
                $cont.removeClass(options.cssWarning);
            }
            if(available < 0){
                $cont.addClass(options.cssExceeded);
            } else {
                $cont.removeClass(options.cssExceeded);
            }
            $cont.html(options.counterText + available);
        };

        this.each(function() {
         // $container is the passed selector, or create the default container
            var $container = (options.container)
                    ? $(options.container)
                        .text(options.counterText)
                        .addClass(options.css)
                    : $('<'+ options.counterElement +' class="' + options.css + '">'+ options.counterText +'</'+ options.counterElement +'>').insertAfter(this);
            calculate(this,$container);
            $(this).keyup(function(){calculate(this,$container)});
            $(this).change(function(){calculate(this,$container)});
        });

    };
})(jQuery);

Answer 1

Have you tried ​the maxlength attribute? That will block input once the character limit is reached.

<textarea maxlength='150'></textarea>​​​​​​​​​​​​​​​​​​​​​​​​​​ // Won't work
<input type='text' maxlength='150' />

Edit It appears that maxlength for a textarea works in Chrome, but not in other browsers, my bad. Well, another approach would just be to monitor keydown events and if length>150, return false/preventDefault/however you want to stop the default action. You'd still want allow backspace and enter however, so monitor keycode as well.

$('#yourTextarea').keydown(function(e) {
    if (this.value.length > 150) 
        if ( !(e.which == '46' || e.which == '8' || e.which == '13') ) // backspace/enter/del
            e.preventDefault();
});

Answer 2

You're much better off not trying to prevent the user from typing in too many characters and instead showing a counter and only enforcing the character limit when the user tries to submit. The comment boxes Stack Overflow are a decent example. It's both easier technically and more importantly better for the user to do it this way: it's really irritating not to be able to type/paste/drag text into a textarea even if you know there's a character limit.