点击按钮调出选出文件框

<form id="myform">

<input type="email" required />
<input type="email" required />


<a href="javascript:;" class="a-upload" style=" 300px;height: 300px;display: none">
    <input id="aaa" type="file" name="" id="">＋
</a>

<button type="button" onclick="aaaaa()" >aaaaaaaaaaaaa</button>
<input type="submit" value="submit"  id="my" />


</form>

<script type="text/javascript">
/*
    $("#my").click(function () {
        alert("fasfd");
        $("#myform").submit();
    });
*/

function aaaaa()
{
    $("#aaa").click();
}


</script>