JS copy specified content to clipboard sample code_javascript skills

function copyText() {

//Copy content
var txt = document.getElementById("table2").rows[1].cells[0].innerHTML;

//Remove spaces
txt = txt.replace(/ /," ");

//Remove line breaks
txt = txt.replace(/

/," ");
if (window.clipboardData) {
window.clipboardData.clearData();
window.clipboardData.setData("Text", txt);
alert("Copied to clipboard successfully!");
}else if (navigator .userAgent.indexOf("Opera") != -1) {
window.location = txt;
}else if (window.netscape) {
try {
netscape.security.PrivilegeManager. enablePrivilege("UniversalXPConnect");
} catch (e) {
alert("Rejected by browser! Please enter 'about:config' in the browser address bar and press Enter Then set 'signed.applets.codebase_principal_support' to '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("Copied to clipboard successfully!");
}
}