编程艺术中的优质代码片段

function getHTTPObject () {
 if (typeof XMLHttpRequest == 'undefined')
        XMLHttpRequest = function () {
           try {
                return new ActiveXObject('Msxml2.XMLHTTP.6.0');
          } catch (e) {}
           try {
                return new ActiveXObject('Msxml2.XMLHTTP.3.0');
          } catch (e) {}
           try {
                return new ActiveXObject('Msxml2.XMLHTTP');
          } catch (e) {}
           return false;
        }
    return new XMLHttpRequest();
}
// 获取
let request = getHTTPRequest();

function getNextElement (node) {
    if (node.nodeType == 1) {
        return node;
 }
    if (node.nextSibling) {
      return getNextElement(node.nextSibling);
 }
    return null;
}

function addClass (element, value) {
    if (!element.className){
     element.className = value;
   } else {
     var newClassName = element.className;
        newClassName += ' ';
     newClassName += value;
       element.className = newClassName;
    }
}