HTML

<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>

JUERY

<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>