pluscai

 /*
    Duff’s device
     */
    function loop1() {
        var result = [];
        function process(value) {
            result.push(value*2);
        }
        var items = [0,1,2,3,4,5,6,7,8];

pluscai

<h2>不定宽高的图片如何在div中水平垂直居中</h2>
方法1：
<div class="box wraper">
  <img src="http://cdn.jsrun.top/css/img/logo.png" alt="" />
</div>
方法2：
<div class="box wraper2">
  <img src="http://cdn.jsrun.top/css/img/logo.png" alt="" />
</div>
<h2>多行文本如何在div中水平垂直居中</h2>