1- ست کردن یک attr
$("img").attr("src", "http://cdn.css-tricks.com/images/banner.jpg");
2- ست کرد چند attr
$("img").attr({
src: "http://cdn.css-tricks.com/images/banner.jpg",
title: "banner",
alt: "banner"
});
3- گرفتن یک attr
var $source = $("img").attr("src");