file_upload_demo.html

<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>

    <script src="../static/dist/js/jquery-1.11.3.min.js"></script>
    <script src="../static/js/ys_ui_plugin/simple_file_upload.js"></script>
</head>
<body>
    <a href="javascript:void(0)">上传文件</a>

    <img />


    <script>
        $("a").simpleUploadFile({
            changeCallback:function(file){
                var fileReader = new FileReader();
                fileReader.onload = function(){
                    $("img").attr("src",this.result);
                };
                fileReader.readAsDataURL(file);
            }
        });

    </script>

</body>
</html>

simple_file_upload.js

(function($){

    var defaultSettings = {
        acceptTypes:["jpg","png"], // 接受的上传文件类型
        changeCallback:function(file){

        } // 自定义input[type=file] change事件
    };

    var renderHtml = "<input type='file' style='display:none;'/>";

    // 添加隐藏的
    function renderInputFile(target,settings){
        // 生成dialog唯一标识
        var id = "ys_simple_file_upload_"+new Date().getTime()+""+parseInt(Math.random());
        $(target).attr("ys_simple_file_upload",id);
        $(renderHtml).attr("id",id).appendTo("html"); // 添加到文档中去
        return $("#"+id);
    }

    function bindEventHandlers(container,settings){
        var changeCallback = settings.changeCallback;

        $(container).change(function(e){
            e.preventDefault();
            e.stopPropagation();
            var file = e.target.files[0];


            if(!validateFileType(file,settings)){
                alert("文件类型不正确!");
                return;
            }

            changeCallback(file);
        });
    }

    // 验证文件类型
    function validateFileType(file,settings){
        var acceptTypes = settings.acceptTypes;
        var name = file.name;
        var fileSuffix = name.substr(name.lastIndexOf(".")+1);
        for(var i=0;i<acceptTypes.length;i++){
            var acceptType = acceptTypes[i];
            if(acceptType==fileSuffix){
                return true;
            }
        }
        return false;
    }

    var options = {
        simpleUploadFile:function(settings) {
            var mergedSettings = {};

            $.extend(mergedSettings,defaultSettings,settings);

            var container = renderInputFile(this,mergedSettings);

            bindEventHandlers(container,mergedSettings);

            $(this).click(function(e){
                e.preventDefault();
                e.stopPropagation();
                $(container).click();
            });
        }
    };
    $.fn.extend(options);
})(jQuery);