js替代copy(示例代码)

<script type="text/javascript">
function copyCode(id){
var testCode=document.getElementById(id).value;
if(copy2Clipboard(testCode)!=false){
alert("生成的代码已经复制到粘贴板，你可以使用Ctrl+V 贴到需要的地方去了哦！ ");
}
}
copy2Clipboard=function(txt){
if(window.clipboardData){
window.clipboardData.clearData();
window.clipboardData.setData("Text",txt);
}
else if(navigator.userAgent.indexOf("Opera")!=-1){
window.location=txt;
}
else if(window.netscape){
try{
   netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
}
catch(e){
   alert("您的firefox安全限制限制您进行剪贴板操作，请打开'about:config'将
signed.applets.codebase_principal_support'设置为true'之后重试，相对路径为firefox根目
录/greprefs/all.js");
   return false;
}
var clip=Components.classes['@mozilla.org/widget/clipboard;1'].createInstance
(Components.interfaces.nsIClipboard);
if(!clip)return;
var trans=Components.classes['@mozilla.org/widget/transferable;1'].createInstance
(Components.interfaces.nsITransferable);
if(!trans)return;
trans.addDataFlavor('text/unicode');
var str=new Object();
var len=new Object();
var str=Components.classes["@mozilla.org/supports-string;1"].createInstance
(Components.interfaces.nsISupportsString);
var copytext=txt;str.data=copytext;
trans.setTransferData("text/unicode",str,copytext.length*2);
var clipid=Components.interfaces.nsIClipboard;
if(!clip)return false;
clip.setData(trans,null,clipid.kGlobalClipboard);
}
}
</script>
<div>
[<input name="" type="button" value="复制" onclick="copyCode('txtTestCode1')" />]
<br>
<textarea rows=2 id="txtTestCode1" style="width:500px;font-family: Verdana, Arial;font-
size:12px;height:55px;border:1px solid #999999;">复制内容1</textarea>
</div>