function copyToClipboard(txt) {
   if (window.clipboardData) {
    window.clipboardData.clearData();
    clipboardData.setData("Text", txt);
    alert("複製成功！");
 
   } else if (navigator.userAgent.indexOf("Opera") != -1) {
    window.location = txt;
   } else if (window.netscape) {
    try {
     netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
    } catch (e) {
     alert("被瀏覽器拒絕！\n請在瀏覽器位址列輸入'about:config'並回車\n然後將 'signed.applets.codebase_principal_support'設定為'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("複製成功！");
   }
  }