利用Html5实现文件异步上传功能代码实例

<form id="myForm">

    <input type="file" id="u_photo" name="u_photo" />

    <input type="button" id="submit-btn" value="上传" />

</form>

$("#submit-btn").on('click', function() {

    $.ajax({

        url:"/test/upload",

        type:"post",

        data:new FormData($("#myForm").get(0)),

        //十分重要，不能省略

        cache: false,

        processData: false,

        contentType: false,

        success: function () {

            alert("上传成功！");

        }

    });

});

$('#u_photo').on('change', function() {

    var file = this.files[0];

    if (file.size > 1024*1000) {

        alert('文件最大1M！')

    }

});