function showLoginPopup(){
     mMain.showPopup('popup_login');
}
function login(){
    mMain.login();
}
function getInput(which){
    var selector,
        input;
    switch(which){
        case 'mail': selector = 'input#login_email';
            break;
        case 'password': selector = 'input#login_pwd';
            break;
        default : alert("t'as craque ton switch");
    }
    if(!(input=document.querySelector(selector))){
        alert("echec de selector, z'ont change leur DOM");
    } else {
        return input;
    }
}
function fillFields(){
//     var mailInput = getInput('mail')
//         , pwdInput = getInput('password')
//         ;
    getInput('mail').value = credentials.mail;
    getInput('password').value = credentials.pwd;
}
var credentials = {
        mail:'MAIL@EXAMPLE.com',
        pwd: 'PASSWORD'
    }
    ;

    // Displaying the popup isn't necessary as we can call the login action directly
    // (without simulating click event on the "Se connecter" button)
    // showLoginPopup();
    fillFields();
    login();