<input type="button" value="左移"/>
    <input type="button" value="右移"/>
    <div style="width:20px;height:20px;background-color:green;position:absolute;left:100px;top:100px"></div>

<script type="text/javascript">
        $("input[value='左移']").bind("click",function(){
            $("div").animate({
                left: "-=50px"
            },1000)
            })
        $("input[value='右移']").bind("click",function(){
            $("div").animate({
                left: "+=50px"
            },1000)
            })
    </script>