How to clear dxTextBox

Hi Amit,
You can clear the dxTextBox value in the viewShown event handler. So, your code should be as follows:

JavaScript
TestLogOut.Login = function (params) {  
    var viewModel = {  
        //  Put the binding properties here  
        getValue: function () {  
            var email = $("#txtemail").dxTextBox('option', 'value');  
            var pwd = $("#txtpwd").dxTextBox('option', 'value');  

            if (email == 'x' && pwd == '123') {  
                TestLogOut.app.navigate('StartPage', { root: true });  
            }  
        },  
        viewShown: function (e) {  
            $("#txtemail").dxTextBox('instance').option('value', '');  
            $("#txtpwd").dxTextBox('instance').option('value', '');  
        }  

    };  
    return viewModel;  
};  

Alternatively, disable a view cache by setting the HtmlApplication.disableViewCache option to true as shown below:

JavaScript
TestLogOut.app = new DevExpress.framework.html.HtmlApplication({  
        namespace: TestLogOut,  
        defaultLayout: TestLogOut.config.defaultLayout,  
        navigation: TestLogOut.config.navigation,  
        disableViewCache: true  
});