jquery实现ajax文件上传

< form id = "form1" name = "form1" >
  < input type = "file" name = "fileToUpload" id = "fileToUpload"  multiple = "multiple" />
  < progress id = "progressBar" value = "0" max = "100" ></ progress >
  < span id = "percentage" ></ span >
  < input type = "button" onclick = "UpladFile()" value = "Upload" />
</ form >

<script type= "text/javascript" >
$(document).ready( function () {
    $( '#form1' ).submit( function () {
    var formdata =  new FormData();
    var fileObj = document.getElementById( "fileToUpload2" ).files;
        for ( var i = 0; i < fileObj.length; i++)
        formdata.append( "file" + i, fileObj[i]);
        $.ajax({
            type:  'POST' ,
            url:  '/Home/Upload2' ,
            data: formdata,
            /**
                            *必须false才会自动加上正确的Content-Type
             */
            contentType:  false ,
            /**
            * 必须false才会避开jQuery对 formdata 的默认处理
            * XMLHttpRequest会对 formdata 进行正确的处理
            */
            processData:  false
        }).then( function () {
            alert( 'done' );
        },  function () {
            //failCal
        });
        return false ;
    });
});
function ajaxUpload() {
    $( "#form1" ).submit();
}
</script>