                        课程
                    
                        /前端开发
                        
                            /jQuery
                        
                        /jQuery基础课程

求大神看下为什么不行？

<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <script src="http://libs.baidu.com/jquery/1.9.0/jquery.js" type="text/javascript"></script>>
        <title>jQuery动画特效</title>
        <style type="text/css">
            #pt{
            	margin:200px;
            	background: red;
            	width: 100px;
            	height: 100px;
            }
            #ipt{
            	position: absolute;
            	top: 0;
            	left: 10;
            }
        </style>
    </head>
    
    <body>
    	<div id="pt"></div>
    	<div id="ipt">
	        <input type="button" value="向左" id="left" />
	        <input type="button" value="向右" id="right" />
        </div>
        
        <script type="text/javascript">
        $("#left").bind("click",function(){
			
			$("#pt").animate({left: "+=50px"},2000)
		})
		$("#right").bind("click",function(){
			
			$("#pt").animate({left:"-=50px"},2000)
		})
		
        </script>
    </body>
</html>