上传文件之前本地预览

<script type="text/javascript">
        $(document).ready(function () {
            $("#File1").bind("change", function () {
                var f = document.getElementById('File1').files[0];
                var src = window.URL.createObjectURL(f);                

                $("#img1").attr("src", src)
               
            })
           
        });
    </script>