I have a login button with onclick event...onclick = "login();"
I successfully logged in ...but I wanted to open new tab instead.
This is my javascript:
login = function() {
    if ($("#UserName").val().length == 0) {
        return;
    }
    if ($("#Password").val().length == 0) {
        return;
    }
    var logindata = new Object();
    logindata.UserName = $("#UserName").val();
    logindata.Password = $("#Password").val();
    locustraxx.showLoading("loginformDiv");
    locustraxx.doAjaxPostback('//example.com/LoginHandler.ashx', logindata, null, null,
        function(data, textStatus, jqXHR) {
            var isChrome = /Chrome/.test(navigator.userAgent) && /Google Inc/.test(navigator.vendor);
            if (data.success == true) {
                if ($("#Remember").is(':checked')) {
                    $.cookie('remember', $("#UserName").val() + '|' + $("#Password").val(), {
                        expires: 36500,
                        path: '/'
                    });
                }
                var retUrl = $.QueryString("ReturnUrl");
                if (retUrl == undefined || retUrl == null) {
                    window.location.replace(data.data, '_blank');
                } else {
                    window.location.href = decodeURIComponent(retUrl).replace(/\~~/g, ".");
                }
                if (isChrome) {
                    // clearCookies();
                }
                return false;
            } else {
                alert(data.message);
                $("#UserName").focus();
            }
        }, null,
        function() {
            login.hideLoading("loginformDiv");
        });
}
I tried _blank... window open, but to no avail
 
     
    