/**
 * TextAreaExpander plugin for jQuery
 * v1.0
 * Expands or contracts a textarea height depending on the
 * quatity of content entered by the user in the box.
 *
 * By Craig Buckler, Optimalworks.net
 *
 * As featured on SitePoint.com:
 * http://www.sitepoint.com/blogs/2009/07/29/build-auto-expanding-textarea-1/
 *
 * Please use as you wish at your own risk.
 */

/**
 * Usage:
 *
 * From JavaScript, use:
 *     $(<node>).TextAreaExpander(<minHeight>, <maxHeight>);
 *     where:
 *       <node> is the DOM node selector, e.g. "textarea"
 *       <minHeight> is the minimum textarea height in pixels (optional)
 *       <maxHeight> is the maximum textarea height in pixels (optional)
 *
 * Alternatively, in you HTML:
 *     Assign a class of "expand" to any <textarea> tag.
 *     e.g. <textarea name="textarea1" rows="3" cols="40" class="expand"></textarea>
 *
 *     Or assign a class of "expandMIN-MAX" to set the <textarea> minimum and maximum height.
 *     e.g. <textarea name="textarea1" rows="3" cols="40" class="expand50-200"></textarea>
 *     The textarea will use an appropriate height between 50 and 200 pixels.
 */

// jQuery plugin definition
var TextAreaExpander = function(e) {

	var hCheck = !(Prototype.Browser.IE || Prototype.Browser.Opera);

	// resize a textarea
	function ResizeTextarea(e) {
	
		// event or initialize element?
		e = e.target || e;
	
		// find content length and box width
		var vlen = e.value.length, ewidth = e.offsetWidth;
		if (vlen != e.valLength || ewidth != e.boxWidth) {
	
			if (hCheck && (vlen < e.valLength || ewidth != e.boxWidth)) e.style.height = "0px";
			var h = Math.max(e.expandMin, Math.min(e.scrollHeight, e.expandMax));
	
			e.style.overflow = (e.scrollHeight > h ? "auto" : "hidden");
			e.style.height = (Prototype.Browser.WebKit ? h - parseInt(e.getStyle('padding-top')) - parseInt(e.getStyle('padding-bottom')) + "px" : h + "px");
			//e.style.height = h + "px";
	
			e.valLength = vlen;
			e.boxWidth = ewidth;
		}
	
		return true;
	};

	
	// is a textarea?
	if (e.nodeName.toLowerCase() != "textarea") return;

	// set height restrictions
	var p = e.className.match(/expand(\d+)\-*(\d+)*/i);
	e.expandMin = p ? parseInt('0'+p[1], 10) : 0;
	e.expandMax = p ? parseInt('0'+p[2], 10) : 99999;

	// initial resize
	//ResizeTextarea(e);

	// zero vertical padding and add events
	if (!e.Initialized) {
		e.Initialized = true;
		$(e).setStyle("padding-top", 0).setStyle("padding-bottom", 0);
		$(e).observe("keyup", ResizeTextarea).observe("focus", ResizeTextarea);
	}

	return this;
};


// initialize all expanding textareas
Event.observe(document, 'dom:loaded', function() {
	$$("textarea[class*=expand]").each(function(e) {
		new TextAreaExpander(e);
	});
});
/*jQuery(document).ready(function() {
	jQuery("textarea[class*=expand]").TextAreaExpander();
});*/