Ошибка в JS Uncaught TypeError: $ is not a function

У меня возникла ошибка в Js Uncaught TypeError: $ is not a function

<script>
    function checkParams(event) {
        var name = $('#name').val();
        var email = $('#email').val();

        if(name.length != 0 && email.length != 0 ) {
            console.log('1');
        } else {
            console.log('2');
        }
     }      
 </script>

    <form enctype="multipart/form-data" id="form_newdead" method="POST">
        <input  type="text" name="name"  placeholder="Как вас зовут?"autocomplete="off"  id="name"  onkeyup="checkParams(event);">

        <input  id="email" type="text" name="email""autocomplete="off" placeholder="Ваш Email"  
            onkeyup="checkParams(event);">
</form>