function nav(){
    $("#nav ul").css({display: "none"});
    $("#nav li").hover(function(){
    $(this).find('ul:first').css({visibility: "visible",display: "none"}).show(400);
    },function(){
    $(this).find('ul:first').css({visibility: "hidden"});
    });
}

function equal_height() {
    var left_height = $('#content').height();
    var right_height = $('#sidebar').height();
    if(right_height > left_height) {
        $('#content').height(right_height);
    }
}
    
$(document).ready(function(){					
    nav();
    equal_height();
});