<script>
    $("#banner_img_show").on('click', function(){
        $("#banner_input_file").click();
    });
    $("#banner_input_file").on("change", headPortraitListener);

    /*定义全局变量存贮图片信息*/
    var base64head = "";

    /*上传监听*/
    function headPortraitListener(e) {
        var img = document.getElementById('banner_img_show');
        if (window.FileReader) {
            var file = e.target.files[0];
            var reader = new FileReader();
            if (file && file.type.match('image.*')) {
                reader.readAsDataURL(file);
            } else {
                img.css('display', 'none');
                img.attr('src', '');
            }
            reader.onloadend = function (e) {
                img.setAttribute('src', reader.result);
                base64head = reader.result;
            }
        }
    }
</script>