iframeUpload

废话没有，直接代码：

(function(ns) {
    function IframeUpload(options) {
        var config = {
            obj: null,
            action: "",
            beforeUpload:null,
            afterUpload: null
        },
        __self__ = this;
        for (var a in options) {
            config[a] = options[a];
        }
        this.config = config;
        var iframe = document.createElement("iframe");
        iframe.setAttribute("src", "javascript:void(0)");
        iframe.style.display="none";
        iframe.addEventListener("load", function() {
            __self__.config.afterUpload && __self__.config.afterUpload.call(__self__,this.contentWindow.document.body.innerHTML);
        },
        false);
        document.body.appendChild(iframe);
        this.iframe = iframe;
        this.form = null;
        this.file = null;
    }
    IframeUpload.prototype = {
        prepare: function() {
            var __self__ = this;
            var form = document.createElement("form");
            form.setAttribute("method", "post");
            form.setAttribute("target", "_self");
            form.setAttribute("enctype", "multipart/form-data");
            form.setAttribute("action", this.config.action);
            this.iframe.contentWindow.document.body.appendChild(form);

            var file = this.config.obj.cloneNode(true);
            form.appendChild(file);

            this.form = form;
            this.file = file;
        },
        upload: function() {
            this.prepare();
            this.form.submit();
        },
        afterUpload: function() {},
        beforeUpload:function(){}
    }
    ns.IframeUpload = IframeUpload;
})(this)

只针对firefox，新手慎用。