纯JS为DOM添加html字符串：appendHTML方法和prependHTML方法

appendHTML:

HTMLElement.prototype.appendHTML = function(html) {
    var divTemp = document.createElement("div"), nodes = null
        // 文档片段，一次性append，提高性能
        , fragment = document.createDocumentFragment();
    divTemp.innerHTML = html;
    nodes = divTemp.childNodes;
    for (var i=0, length=nodes.length; i<length; i+=1) {
       fragment.appendChild(nodes[i].cloneNode(true));
    }
    this.appendChild(fragment);
    // 据说下面这样子世界会更清净
    nodes = null;
    fragment = null;
};

prependHTML:

var prependHTML = function(el, html) {
    var divTemp = document.createElement("div"), nodes = null
        , fragment = document.createDocumentFragment();

    divTemp.innerHTML = html;
    nodes = divTemp.childNodes;
    for (var i=0, length=nodes.length; i<length; i+=1) {
       fragment.appendChild(nodes[i].cloneNode(true));
    }
    // 插入到容器的前面 - 差异所在
    el.insertBefore(fragment, el.firstChild);
    // 内存回收？
    nodes = null;
    fragment = null;
};

转自：http://www.zhangxinxu.com/wordpress/2013/05/js-dom-basic-useful-method/