I cannot figure out what I'm doing wrong syntactically here:

function PlaceOrder(button)
{
    var isValid;

    if (buttonIsSelected())
    {
        showsMessage(btn, "showTestMessage2);
        isValid = true;
    }
    else
    {
        Page_ClientValidate();
        if (Page_IsValid)
        {
            showMessage(btn, "testMessage");
            isValid = true;
        }
    }

    return isValid; // error happens here
}