function check(username, password) {
    if (username == "" && password == "") {
        window.alert("Please enter your Username & Password");
    } else if (username == "") {
        window.alert("Please enter your Username");
    } else if (password == "") {
        window.alert("Please enter your Password");
    } else {
        Ext.Ajax.request({
            url: 'database.php',
            params: {
                uname: username
            },
            success: function (response, opts) {

            }
        });

    }
}