复制到剪贴板方法

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("您使用的浏览器不支持此复制功能，请使用ctrl+c或者浏览器右键复制");
      }
      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);
   }
   return true;
}