急：一文本删除节点，但保存节点内文本怎么做？

如：
<div>aasdfasdgadfasdfasd<span>DDD</span>
asdfasdfasdf
</div>
我要把span这个节点给去掉，但要使DDD保存再原来的位置，需要怎么做？

document.getElementByTagName("span").display="none"; //去除spandocument.getElementByTagName("span").display="inline"; //显示span
<div id='divTest'>aasdfasdgadfasdfasd<span>DDD</span>
asdfasdfasdf
</div>var divTest=document.getElementById("divTest");
divTest.innerHTML = divTest.innerHTML.replace(/<\/?span.*?>/i,"");
var div=...;
div.innerHTML=div[('textContent' in div)?'textContent':innerText];