jQuery, textarea resize

Question

So I have the standard textarea autogrow code below, which I've changed to bind on input propertychange so as to capture pastes.

(function($)
{
    $.fn.autogrow = function(options)
    {
        return this.filter('textarea').each(function()
        {
            var self         = this;
            var $self        = $(self);
            var minHeight    = $self.height();
            var noFlickerPad = $self.hasClass('autogrow-short') ? 0 : parseInt($self.css('lineHeight')) || 0;
            var settings = $.extend({
                preGrowCallback: null,
                postGrowCallback: null
              }, options );

            var shadow = $('<div></div>').css({
                position:    'absolute',
                top:         -10000,
                left:        -10000,
                width:       $self.width(),
                fontSize:    $self.css('fontSize'),
                fontFamily:  $self.css('fontFamily'),
                fontWeight:  $self.css('fontWeight'),
                lineHeight:  $self.css('lineHeight'),
                resize:      'none',
                'word-wrap': 'break-word'
            }).appendTo(document.body);

           $self.bind('input propertychange', function()
            {
                var times = function(string, number)
                {
                    for (var i=0, r=''; i<number; i++) r += string;
                    return r;
                };

                var val = self.value.replace(/&/g, '&amp;')
                                    .replace(/</g, '&lt;')
                                    .replace(/>/g, '&gt;')
                                    .replace(/\n$/, '<br/>&#xa0;')
                                    .replace(/\n/g, '<br/>')
                                    .replace(/ {2,}/g, function(space){ return times('&#xa0;', space.length - 1) + ' ' });

                // Did enter get pressed?  Resize in this keydown event so that the flicker doesn't occur.
                if (event && event.data && event.data.event === 'keydown' && event.keyCode === 13) {
                    val += '<br />';
                }

                shadow.css('width', $self.width());
                shadow.html(val + (noFlickerPad === 0 ? '...' : '')); // Append '...' to resize pre-emptively.

                var newHeight=Math.max(shadow.height() + noFlickerPad, minHeight);
                if(settings.preGrowCallback!=null){
                  newHeight=settings.preGrowCallback($self,shadow,newHeight,minHeight);
                }

                $self.height(newHeight);

                if(settings.postGrowCallback!=null){
                  settings.postGrowCallback($self);
                }
            });
        });
    };
})(jQuery);

I've been trying to get the textarea on initialisation to be the same height as the text. I've seen people use all sorts, e.g.

$(this).height(0).height(this.scrollHeight);

This doesn't work. The other thing I've down is mimicked a keydown event to the textarea, that expands the textarea for certain however it ends up with a lot of whitespace after the text and far too large.

Any suggestions on how to ensure the textarea fits the text even on initialisation? Thanks.

Answer 1

Here is a functioning code:-

(function($)
{
    $.fn.autogrow = function(options)
    {
        return this.filter('textarea').each(function()
        {
        this.setAttribute('style', 'height:' + (this.scrollHeight) + 'px;overflow-y:hidden;');
        }).on('input', function () {
          this.style.height = 'auto';
          this.style.height = (this.scrollHeight) + 'px';
        });
    };
})(jQuery);

The problem with scrollHeight not working is the textarea was in a div area that was being made invisible by jQuery on document ready. This gave a scrollHeight undefined.

The answer is to introduce a timeout to address that problem 1 second after load to hide the divs, once the textareas have all been properly resized.