定义和用法

draggable 上的 start、drag 和 stop 事件。拖拽开始时触发 start 事件，拖拽期间触发 drag 事件，拖拽停止时触发 stop 事件

示例

<!DOCTYPE html><html><head>	<meta charset="utf-8">	<meta http-equiv="X-UA-Compatible" content="IE=edge">	<title>jQuery UI 拖动（Draggable） - 事件</title>	<link rel="stylesheet" href="js/jquery-ui-1.12.1.custom/jquery-ui-1.12.1.custom/jquery-ui.min.css">	<style>		#draggable{			width: 16em;			padding: 0 1em;		}		#draggable ul li{			margin:1em 0;			padding:0.5em 0;		}		#draggable ul li span.ui-icon{			float: left;		}		#draggable ul li span.count{			font-weight: bold;		}	</style></head><body>	<div id="draggable" class="ui-widget ui-widget-content">		<p>请拖拽我，触发一连串的事件。</p>		<ul class="ui-helper-reset">			<li id="event-start" class="ui-state-default ui-corner-all">				<span class="ui-icon ui-icon-play">"start" 被调用</span>				<span class="count">0</span>x "start" 被调用			</li>			<li id="event-drag" class="ui-state-default ui-corner-all">				<span class="ui-icon ui-icon-arrow-4">"drag" 被调用</span>				<span class="count">0</span>x "drag" 被调用			</li>			<li id="event-stop" class="ui-state-default ui-corner-all">				<span class="ui-icon ui-icon-stop">"stop" 被调用</span>				<span class="count">0</span>x "stop" 被调用			</li>		</ul>	</div>	<script class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="js/jquery-ui-1.12.1.custom/jquery-ui-1.12.1.custom/external/jquery/jquery.js" type="text/javascript" ></script>	<script class="lazyload" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC" data-original="js/jquery-ui-1.12.1.custom/jquery-ui-1.12.1.custom/jquery-ui.min.js"></script>	<script>		//获取对象		var $start_counter = $("#event-start"),		$drag_counter = $("#event-drag"),		$stop_counter = $("#event-stop"),		counts = [0,0,0];		$("#draggable").draggable({			start:function(){				counts[0]++;				updateCounterStatus($start_counter,counts[0]);			},			drag:function(){				counts[1]++;				updateCounterStatus($drag_counter,counts[1]);			},			stop:function(){				counts[2]++;				updateCounterStatus($stop_counter,counts[2]);			}		});		/**		 * 更新数值		 * @param  {[object]} $event_counter [li对象]		 * @param  {[int]} new_count      [次数]		 */		function updateCounterStatus($event_counter,new_count){			if (!$event_counter.hasClass('ui-state-hover')) {				$event_counter.addClass('"ui-state-hover"')				.siblings().removeClass('ui-state-hover');			}			$("span.count",$event_counter).text(new_count);		}	</script></body></html>