SOURCE

console 命令行工具 X clear

                    
>
console
function foo() {
    var a = 2;

    function bar() {
        console.log( a );
    }

    return bar;
}

var baz = foo();

baz(); // 2 -- 哇噢,看到闭包了,伙计。
<div id="position">水平垂直居中的对象</div>
#position {
    background-color:red;
    position:absolute;
    top: 50%;
    left: 50%;
    width:200px;
    height: 40px;
    margin: -20px 0 0 -100px;
    /* padding: 0 20px; */
    line-height:240%;
     text-align:center;  
}

@media screen and (max-width:599px) {
  nav li {
    display: inline;
  }
}

@media screen and (max-width:100px){
  #position {
    background-color:blue;
  }
}
body{
    background-color:green;
}