<form id= "uploadForm">  
      <p >指定文件名: <input type="text" name="filename" value= ""/></p >  
      <p >上传文件: <input type="file" name="file"/></ p>  
      <input type="button" value="上传" onclick="doUpload()" />  
</form>  
function doUpload() {  
     var formData = new FormData($( "#uploadForm" )[0]);  
     $.ajax({  
          url: ‘http://localhost:8080/cfJAX_RS/rest/file/upload‘ ,  
          type: ‘POST‘,  
          data: formData,  
          async: false,  
          cache: false,  
          contentType: false,  
          processData: false,  
          success: function (returndata) {  
              alert(returndata);  
          },  
          error: function (returndata) {  
              alert(returndata);  
          }  
     });  
}  
原文:http://www.cnblogs.com/laobiao/p/5635802.html