关于document.createTextNode

<SCRIPT>
function fnChangeNode(){
var oTextNode = document.createTextNode("New Text\r\ndd");
var oReplaceNode = oSpan.childNodes(0);
oReplaceNode.replaceNode(oTextNode);
}
</SCRIPT>
<SPAN ID="oSpan" onclick="fnChangeNode()">
Original Text
</SPAN>
为何"New Text\r\ndd"显示不了换行
只显示空格