js复制代码特效是在textarea里面的内容，通过点击，就把里面的内容复制一遍，就可以使用ctrl+v使用，就相当于把textarea里面的内容ctrl+c。

<input type=”button” value=”复制代码” onclick=”doCopy(‘daima’)” /><br />
<script>
function doCopy(ID) {
if (document.all){
textRange = document.getElementById(ID).createTextRange();
textRange.execCommand(“Copy”);
alert(“复制成功”);
}
else{
//alert(“此功能只能在IE上有效”);
copyToClipboard(document.getElementById(ID).value);
}
}
function copyToClipboard(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(“被浏览器拒绝！\n请在浏览器地址栏输入’about:config’并回车\n然后
将’signed.applets.codebase_principal_support’设置为’true'”);
}
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>
<textarea id=”daima” name=”daima” style=”height:600px;width:960px;”>asfsdfsdfsdfsd</textarea>