Android app doesn't create and access SQLite database

I am new to app developing and I chose phonegap to create one. I have find difficulties to create an SQLite Database, in order to get data from a form which purpose is to register the users. I followed the instruction in the phonegap docs and also I checked for similar posts online and in stackoverflow but i can't find what's wrong. When i run it doesn't give me any alerts about the database and keeps returning me back on the my first page. Below is the code.

     <script type="text/javascript">
                 document.addEventListener("deviceready" , OnDeviceReady , false);

        function OnDeviceReady(){
            var database = window.openDatabase("PuzzledDB","1.0","Puzzled",20000);
            database.transaction(populateDB,errorDB,successDB);
        }

        function populateDB(tx){
            tx.executeSql("CREATE TABLE IF NOT EXISTS Users (Username text, Password text, Email text, Role text)");
        }

        function errorDB(tx,error){
            alert("Error processing SQL: "+err.code);
        }

        function successDB(){
            alert("success!");
        }

        function Users(){
            var username1 = document.getElementById("username").value;
            var password1 = document.getElementById("password").value;
            var email1 = document.getElementById("email").value;
            var role1 = document.getElementById("role").value;

             var database = window.openDatabase("PuzzledDB","1.0","Puzzled",20000);
             database.transaction(function(tx){
             NewUser(tx,username1,password1,email1,role1);},ErrorRegistration,SuccessRegistration);
             }
        }

        function NewUser(tx,username1,password1,email1,role1){
            tx.executeSql("INSERT INTO TABLE Users (Username,Password,Email,Role) VALUES ("+ username1 +",'"+ password1 +"','"+ email1 +"','"+ role1 +"')");
        }

        function ErrorRegistration(tx,error){
            alert("Error processing SQL: "+err.code);
        }

        function SuccessRegistration(){
            alert("success!");
            });
        }

    </script>

        <div data-role="page" id="pagefour" data-theme="c">
    <div class="header" id="header" data-role="header">
    <h3>Δημιουργια Λογαριασμου</h3>
    </div>
    <div id="wrapper">
        <form>
            <div data-role="main" class="ui-content"  style="color:white">
                <div class="username" data-role="ui-field-contain">
                    <label class="ui-hidden-accessible"> Όνομα Χρήστη </label>
                    <input type="text" id="username" name="username" value="" placeholder="Όνομα Χρήστη">
                </div>
                <div class="password" data-role="ui-field-contain">
                    <label class="ui-hidden-accessible"> Κωδικός </label>
                    <input type="password" id="password" name="password" value="" placeholder="Κωδικός">
                </div>
                <div class="email" data-role="ui-field-contain">
                    <label class="ui-hidden-accessible"> Email </label>
                    <input type="email" id="email" name="email" value="" placeholder="Email">
                </div>
                <div class="role" data-role="ui-field-contain">
                    <label class="ui-hidden-accessible"> Ρόλος </label>
                    <input type="text" id="role" name="role" value="" placeholder="Ρόλος">
                </div>
                <div class="register" data-role="ui-field-contain">
                <input id="register" value="Υποβολη" type="submit" name="Register" onclick="Users();">
                </div>
             </div>
        </form>
    </div>
</div>

Thanks in advance for any help!!