js添加DOM元素.txt

var asideNav = document.getElementById('aside-nav'),//导航
    oCons = document.getElementById('construction'),//内容
    oh4 = oCons.querySelectorAll('h4');
    frag = document.createDocumentFragment(),//Dom碎片
    createObj = null,//创建元素
    min = oCons.offsetTop,
    max = min + oCons.scrollHeight,
    aTop = document.getElementById('top');

for (var i = 0; i < oh4.length; i++) {
    createObj = document.createElement('a');//创建元素
    createObj.innerText = oh4[i].innerText;
    oh4[i].id='title'+i;
    createObj.href = '#' + oh4[i].id;
    frag.appendChild(createObj);//先添加到Dom碎片中
}
asideNav.appendChild(frag);一次性添加到DOM树下面渲染.