jQuery.ready() == window.onload
$(document).ready(function() {
alert("안녕하세요");
});
$("#frontEnd").css("border","1px solid #ff00ff");
$("#backEnd").css("border","1px solid #00ffff");
$(".java").css("background", "wheat");
$("h2").css("text-decoration","underline");
$("[href]").css("background", "pink");
$("[href$=js]").css("background", "lightgreen");