var oDiv = document.getElementById("guoDiv"); var oSpan = document.createElement("span"); oSpan.innerHTML = "4"; var firsChild = oDiv.firstElementChild ? oDiv.firstElementChild : oDiv.firstChild var returnNode = oDiv.replaceChild(oSpan, firsChild); //替换第一个元素,返回被替换掉的元素 alert(returnNode.innerHTML); //1 var lastChild = oDiv.lastElementChild ? oDiv.lastElementChild : oDiv.lastChild; oSpan = document.createElement("span"); oSpan.innerHTML = "5"; returnNode = oDiv.replaceChild(oSpan, lastChild); //替换最后一个,返回被替换掉的元素 alert(returnNode.innerHTML);//3

<div id="guoDiv"> <span>1</span> <span>2</span> <span>3</span> </div>