Add reply button(s) plugin for Talkerapp

plugin.replyButton.js

// https://cheeaun.talkerapp.com/plugins/56

(function(plugin, $){
	var msgbox = $('#msgbox');
	
	// Gladly stolen from
	// http://github.com/mootools/mootools-more/blob/master/Source/Element/Element.Forms.js
	var selectRange = function(el, start, end){
		if (el.setSelectionRange) {
			el.focus();
			el.setSelectionRange(start, end);
		} else {
			var value = el.value;
			var diff = value.substr(start, end - start).replace(/\r/g, '').length;
			start = value.substr(0, start).replace(/\r/g, '').length;
			var range = el.createTextRange();
			range.collapse(true);
			range.moveEnd('character', start + diff);
			range.moveStart('character', start);
			range.select();
		}
	};
	
	var setCaretPosition = function(el, pos){
		if (pos == 'end') pos = el.value.length;
		selectRange(el, pos, pos);
	};
	
	$('tr.message').live('mouseover', function(){
		var el = $(this);
		var message = el.find('td.message');
		var replyButton = message.find('a.reply-button');
		if (!replyButton.length){
			var replyContainer = $('<div class="reply-button-container"></div>').css('position', 'relative');
			replyButton = $('<a href="#" class="reply-button">Reply</a>').css({
				position: 'absolute',
				right: 9,
				bottom: 4,
				backgroundColor: '#fff',
				padding: '3px 8px',
				fontSize: '.8em',
				textTransform: 'uppercase',
				'-moz-border-radius': '3px',
				'-webkit-border-radius': '3px'
			}).appendTo(replyContainer);
			replyContainer.appendTo(message);
		}
		replyButton.show();
	}).live('mouseout', function(){
		var el = $(this);
		var message = el.find('td.message');
		var replyButton = message.find('a.reply-button');
		if (!replyButton.length) return;
		replyButton.hide();
	});
	
	$('tr.message a.reply-button').live('click', function(){
		var el = $(this);
		var message = el.parents('tr.message');
		if (!message.length) return;
		var author = message.attr('author');
		var val = $.trim(msgbox.val());
		var pattern = new RegExp('@' + author + '(\\s|$)', 'gi');
		if (val === ''){
			msgbox.val('@' + author + ' ');
		} else if (!pattern.test(val)){
			msgbox.val(val + ' @' + author);
		}
		setCaretPosition(msgbox[0], 'end');
		msgbox.focus();
		return false;
	});
})(plugin, jQuery);