// how to use $("#hoge").visible(function () { console.log("（＜●＞д＜●＞）", this); }, function () { console.log("（ ― д ― ）", this); });

gistfile1.js

// uncompress
;(function ($) {
    $.fn.visible = function (visible, invisible) {
        if ((typeof visible !== "function") && (typeof invisible !== "function")) {
            return this;
        }
        
        return this.each(function () {
            if ($(this).css('display') === 'none') {
                invisible.apply(this);
            } else {
                visible.apply(this);
            }
        });
    };
})(jQuery || Zepto);


// compress
// ;(function(a){a.fn.visible=function(b,c){return"function"!==typeof b&&"function"!==typeof c?this:this.each(function(){"none"===a(this).css("display")?c.apply(this):b.apply(this)})}})(jQuery||Zepto);

$("#hoge").visible(function(){

}).invisible(function(){

});