jQuery.fn.tarea = function(options) {

    return this.each(function() {
        var $textarea = $(this);
        $textarea.on('blur', function (e) {
            ...
            options.callback(e, $textarea.val());			
        });
    });
};

$("#myForm textarea").tarea({
    ...
    callback: function(e, value) {
        $.ajax({
            'url': 'action.php',
            'data': {'text': value, 'id': $(e.target).data('id')}
        });
    });
});

jQuery.fn.tarea = function(options) {
    console.log(options)
    ...

jQuery.fn.tarea = function(options) {
    return this.each(function() {
        var $textarea = $(this);
        $textarea.on('blur', function (e) {
            options.callback(e, $textarea.val());            
        });
    });
};       

$("#ta textarea").tarea({
    callback: function(e, value) {
        alert(e.target.id + ' ' + value);
    }
});

for (var i = 1; i<4; i++) {
    $("<textarea id='textarea"+ i +"'>text"+ i +"</textarea>").appendTo("#ta").tarea({
        callback: function(e, value) {
            alert(e.target.id + ' ' + value);
        }
    });
}

jQuery.fn.autoGrow = function(options) {

	// context
    var self = this;
    
	// default settings
	self.options = $.extend({
		'editor': true,
		'toggle': false,
        'callback': false
	}, options || {});

	return self.each(function() {

		var $textarea = $(this)
			.css('overflow','hidden')
			.css('minHeight',this.rows+'em');
			
		if ($textarea.next('.autogrow-textarea-mirror').length) {
			$mirror = $textarea.next('.autogrow-textarea-mirror').eq(0)
		} else {
			var $mirror = $('<div class="autogrow-textarea-mirror"></div>')
				.css('wordWrap', 'break-word')
				.css('borderColor', 'transparent')
				.css('fontFamily',        $textarea.css('font-family'))
				.css('fontSize',          $textarea.css('font-size'))
				.css('lineHeight',        $textarea.css('line-height'))
				.css('borderTopStyle',    $textarea.css('borderTopStyle')) //for cross-browser compatibility don't use shorthand properties
				.css('borderBottomStyle', $textarea.css('borderBottomStyle'))
				.css('borderLeftStyle',   $textarea.css('borderLeftStyle'))
				.css('borderRightStyle',  $textarea.css('borderRightStyle'))
				.css('borderTopWidth',    $textarea.css('borderTopWidth'))
				.css('borderBottomWidth', $textarea.css('borderBottomWidth'))
				.css('borderLeftWidth',   $textarea.css('borderLeftWidth'))
				.css('borderRightWidth',  $textarea.css('borderRightWidth'))
				.css('marginTop',         $textarea.css('marginTop'))
				.css('marginBottom',      $textarea.css('marginBottom'))
				.css('margingLeft',       $textarea.css('margingLeft'))
				.css('marginRight',       $textarea.css('marginRight'))
				.css('paddingTop',        $textarea.css('paddingTop'))
				.css('paddingBottom',     $textarea.css('paddingBottom'))
				.css('paddingLeft',       $textarea.css('paddingLeft'))
				.css('paddingRight',      $textarea.css('paddingRight'))
				.hide().insertAfter($textarea);
		}
			
		var sendContentToMirror = function () {
			$mirror.html($textarea.val().replace(/\n/g, '<br/>') + '&nbsp').show() //incorrect calculation of height if mirrow is hidden
			if ($textarea.height() !== $mirror.height()) {
				$textarea.height($mirror.height());
            }
			$mirror.hide();
		}

		var growTextarea = function () {
			sendContentToMirror();
		}
				
		// Fire the event for text already present
		sendContentToMirror();
				
		// Bind the textarea's event
		this.onkeyup = growTextarea;
		
		// Use settings
		if (!self.options.editor) {
			$mirror.show()
			$textarea.hide()
		}
		
		if (self.options.toggle) {
			$mirror.on('click', function (e) {
				$textarea.show()[0].focus()
				$mirror.hide()				
			});

			$textarea.on('blur', function (e) {
				if(!self.options.editor || $textarea.val()){
					$textarea.hide()
					$mirror.show()
					
                    self.options.callback(e, $textarea.val());
				}				
			});
		}
	});
};

jQuery.fn.tarea = function(options) {
    return this.each(function() {
        var $textarea = $(this);
        $textarea.on('blur', function (e) {
            options.callback(e, $textarea.val());            
        });
    });
};       

var observer = new WebKitMutationObserver(function(mutations) {
    mutations.forEach(function(mutation) {
        $("#ta textarea").tarea({
            callback: function(e, value) {
                alert(e.target.id + ' ' + value);
            }
        });
    });    
});
observer.observe(document.querySelector('#ta'), {childList: true});

$(document).on('blur', 'textarea', function() { alert($(this).val()); });