ajax 上传文件

<script>

    function f() {

        var d = document.getElementById('file1');

        var v =new XMLHttpRequest();

        v.open('post', 'webform2.aspx');

        v.setRequestHeader("Content-Type", "multipart/form-data");

//        v.onreadystatechange = function (d) {

//                alert(v.responseText);

//        }

        v.send(d.files[0] );

    }

</script>