html 上传文件时 选中文件后自动开始上传

<form  id="bootImg1" action="{{ path('acme_admin_app_dealBootImage') }}  " method="post"  enctype="multipart/form-data">    <div id="bootDiv1">        <input  type="file" name="pic" id="pic1" class="btn btn-info">        <br />        <input type="button" value="上传" onclick="return ajaxup(1);   ">        <input type="hidden" name="imgnum" value=1>        <div style="height:8px;"> </div>    </div></form><script src="{{ asset('public/js/jquery-1.9.1.min.js') }}"></script><script type="text/javascript">    function upload(){        var element = document.getElementById("pic1");        if("\v"=="v")        {            element.onpropertychange = uploadHandle;        }        else        {            element.addEventListener("change",uploadHandle,false);        }        function uploadHandle()        {            if(element.value)            {              // 事件监听到 有改变 就提交form表单                $('#putImg1',window.top.document).html($('<img src="/public/logo/bootImgloading.gif">'));                var ifname = 'up' + Math.random();                $('<iframe name="' + ifname + '" width="0px" height="0px;" frameBorder="0">  </iframe>').appendTo($('body'));                var bootForm =  $('form:first')                var bootForm = $('#bootImg1')                bootForm.attr('target',ifname);                bootForm.submit();//                document.getElementById('bootImg1').submit();            }        }    }</script><script type="text/javascript">    upload();</script>