function update() {

		 var formData = new FormData($( "#contractCollectionForm" )[0])

		$.ajax( {
			url : "upload",
			type : "post",
			contentType : false,
			processData: false,
			data : formData, //此处表单序列化
			dataType : "json",
			success : function(data) {
				alert("保存成功！");
			},
			error : function() {
			}
		});
	}