JS实现复制功能

 <script language="javascript" type="text/javascript">
function footCopyToClipboard(url,content,prom){
 var txt = content+url;
 if(window.clipboardData)
 {
  window.clipboardData.clearData();
  window.clipboardData.setData("Text", txt);
  alert(prom);
 }
  else if(navigator.userAgent.indexOf("Opera") != -1)
  {
   window.location = txt;
   alert(prom);
 }
 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);
  alert(prom);
  }
  txt = null;
}
</script>