合并文本节点

var element = document.createElement("div");
element.className = "message";

var textNode = document.createTextNode("Hello world!");
element.appendChild(textNode);

var anotherTextNode = document.createTextNode("Yippee!");
element.appendChild(anotherTextNode);

document.body.appendChild(element);

console.log(element.childNodes.length); //2

element.normalize();
console.log(element.childNodes.length); //1
console.log(element.firstChild.nodeValue); //Hello world!Yippee!