/**

*	@name							Elastic

*	@descripton						Elastic is Jquery plugin that grow and shrink your textareas automaticliy

*	@version						1.6.4

*	@requires						Jquery 1.2.6+

*

*	@author							Jan Jarfalk

*	@author-email					jan.jarfalk@unwrongest.com

*	@author-website					http://www.unwrongest.com

*

*	@licens							MIT License - http://www.opensource.org/licenses/mit-license.php

*/



(function(jQuery){ 

	jQuery.fn.extend({  

		elastic: function() {

		

			//	We will create a div clone of the textarea

			//	by copying these attributes from the textarea to the div.

			var mimics = [

				'paddingTop',

				'paddingRight',

				'paddingBottom',

				'paddingLeft',

				'fontSize',

				'lineHeight',

				'fontFamily',

				'width',

				'fontWeight'];

			

			return this.each( function() {

				

				// Elastic only works on textareas

				if ( this.type != 'textarea' ) {

					return false;

				}

				

				var $textarea	=	jQuery(this),

					$twin		=	jQuery('<div />').css({'position': 'absolute','display':'none','word-wrap':'break-word'}),

					lineHeight	=	parseInt($textarea.css('line-height'),10) || parseInt($textarea.css('font-size'),'10'),

					minheight	=	parseInt($textarea.css('height'),10) || lineHeight*3,

					maxheight	=	parseInt($textarea.css('max-height'),10) || Number.MAX_VALUE,

					goalheight	=	0,

					i 			=	0;

				var lastValue = $textarea.data('lastValue');

                var currentValue = $textarea.val();

					



				

				// Opera returns max-height of -1 if not set

				if (maxheight < 0) { maxheight = Number.MAX_VALUE; }

					

				// Append the twin to the DOM

				// We are going to meassure the height of this, not the textarea.

				$twin.appendTo($textarea.parent());

				

				// Copy the essential styles (mimics) from the textarea to the twin

				var i = mimics.length;

				while(i--){

					$twin.css(mimics[i].toString(),$textarea.css(mimics[i].toString()));

				}

				

				

				// Sets a given height and overflow state on the textarea

				function setHeightAndOverflow(height, overflow){

					curratedHeight = Math.floor(parseInt(height,10));

					if($textarea.height() != curratedHeight){

						$textarea.css({'height': curratedHeight + 'px','overflow':overflow});

						

					}

				}

				

				

				// This function will update the height of the textarea if necessary 

				function update() {

					

					// Get curated content from the textarea.

					var textareaContent = $textarea.val().replace(/&/g,'&amp;').replace(/  /g, '&nbsp;').replace(/<|>/g, '&gt;').replace(/\n/g, '<br />');



					var twinContent = $twin.html();

					

					if(textareaContent+'&nbsp;' != twinContent){

					

						// Add an extra white space so new rows are added when you are at the end of a row.

						$twin.html(textareaContent+'&nbsp;');

						

						// Change textarea height if twin plus the height of one line differs more than 3 pixel from textarea height

						if(Math.abs($twin.height()+lineHeight - $textarea.height()) > 3){

							

							var goalheight = $twin.height()+lineHeight;

							if(goalheight >= maxheight) {

								setHeightAndOverflow(maxheight,'auto');

							} else if(goalheight <= minheight) {

								setHeightAndOverflow(minheight,'hidden');

							} else {

								setHeightAndOverflow(goalheight,'hidden');

							}

							

						}

						

					}



				}

				

				function watchTextbox() {

                     

  if (lastValue != currentValue) {

    update();

	

  }

}



				

				// Hide scrollbars

				$textarea.css({'overflow':'hidden'});

				

				// Update textarea size on keyup

				$textarea.keyup(function(){ update(); });

				

				// And this line is to catch the browser paste event

				$textarea.live('input paste',function(e){ setTimeout( update, 250); });		

				

				setInterval(watchTextbox, 100);

				

				// Run update once when elastic is initialized

				update();

				

			});

			

        } 

    }); 

})(jQuery);