uncaught reference error $ is not defined
<p>I am getting the following error and no javascript is working on my site:
uncaught reference error $ is not defined</p>

<p>It was working but i cannot now see where there is something wrong Can anyone please help?</p>

<p>I am linking to javascript files here:</p>

<pre><code>    &lt;script src="js/jquery.js" type="text/javascript"&gt;&lt;/script&gt;
&lt;script src="js/jsfunctions.js" type="text/javascript"&gt;&lt;/script&gt;
</code></pre>

<p>And here is the js functions script</p>

<pre><code>//-------------------------- MENU MOVE
$(document).ready(function(){
   $(".one").hover(function() {
       $(this).stop().animate({ marginTop: "5px" }, 200);

    },function(){
        $(this).stop().animate({ marginTop: "0px" }, 300);

    });
});

$(document).ready(function(){
   $(".two").hover(function() {
      $(this).stop().animate({ marginTop: "5px" }, 200);

    },function(){
        $(this).stop().animate({ marginTop: "0px" }, 300);

    });
});


$(document).ready(function(){
   $(".three").hover(function() {
      $(this).stop().animate({ marginTop: "5px" }, 200);

    },function(){
        $(this).stop().animate({ marginTop: "0px" }, 300);

    });
});


$(document).ready(function(){
   $(".four").hover(function() {
      $(this).stop().animate({ marginTop: "5px" }, 200);

    },function(){
        $(this).stop().animate({ marginTop: "0px" }, 300);

    });
});


$(document).ready(function(){
   $(".five").hover(function() {
    $(this).stop().animate({ marginTop: "5px" }, 200);

    },function(){
        $(this).stop().animate({ marginTop: "0px" }, 300);

    });
});


$(document).ready(function(){

    $(".plane").stop().animate({ marginRight: "2000px" }, 40000);


});


$(document).ready(function(){
   $(".signinbutton").hover(function() {
        $(this).stop().fadeTo('slow', 0.5);

    },function(){
        $(this).stop().fadeTo('slow', 1.0);

    });
});

$(document).ready(function(){
   $(".forgotton").hover(function() {
        $(this).stop().fadeTo('slow', 0.5);

    },function(){
        $(this).stop().fadeTo('slow', 1.0);

    });
});


//-------------------------------- SOCIAL FADES
$(document).ready(function(){
   $(".twitter").hover(function() {
        $(this).stop().fadeTo('slow', 0.7);

    },function(){
        $(this).stop().fadeTo('slow', 1.0);

    });
});

$(document).ready(function(){
   $(".facebook").hover(function() {
        $(this).stop().fadeTo('slow', 0.7);

    },function(){
        $(this).stop().fadeTo('slow', 1.0);

    });
});

$(document).ready(function(){
   $(".rss").hover(function() {
        $(this).stop().fadeTo('slow', 0.7);

    },function(){
        $(this).stop().fadeTo('slow', 1.0);

    });
});

//------------------------------------ EMAIL DETAILS


$(function() {

$(".submit").click(function() {

var name = $("#name").val();
var email = $("#email").val();
    var comment = $("#comment").val();
    var dataString = 'name='+ name + '&amp;email=' + email + '&amp;comment=' + comment;

    if(name=='' || email=='' || comment=='')
     {
    alert('Please Give Valid Details');
     }
    else
    {
    $("#flash").show();
    $("#flash").fadeIn(400).html('&lt;img src="../img/-loader.gif" align="absmiddle"&gt;&amp;nbsp;&lt;span class="loading"&gt;Loading Comment...&lt;/span&gt;');
$({
        type: "POST",
  url: "comment.php",
   data: dataString,
  cache: false,
  success: function(html){

  $("ol#update").append(html);
  $("ol#update li:last").fadeIn("slow");
  document.getElementById('email').value='';
   document.getElementById('name').value='';
    document.getElementById('comment').value='';
    $("#name").focus();

  $("#flash").hide();

  }
 });
}
return false;
    });



});

// ----------------------------- Profile Email Check
$(document).ready(function() {

        //the min chars for username
        var min_chars = 3;

        //result texts
        var characters_error = 'Minimum amount of chars is 3';
        var checking_html = 'Checking...';

        //when button is clicked
        $('#check_username_availability').click(function(){
            //run the character number check
            if($('#username').val().length &lt; min_chars){
                //if it's bellow the minimum show characters_error text '
                $('#username_availability_result').html(characters_error);
            }else{
                //else show the cheking_text and run the function to check
                $('#username_availability_result').html(checking_html);
                check_availability();
            }
        });

  });

//function to check username availability
function check_availability(){

        //get the username
        var username = $('#username').val();

        //use  to run the check
        $.post("lib/-checkemail.php", { username: username },
            function(result){
                //if the result is 1
                if(result == 1){
                    //show that the username is available
                    $('#username_availability_result').html(username + ' is not registered. They will be sent an email to invite them to sign up.');
                }else{
                    //show that the username is NOT available
                    $('#username_availability_result').html(username + ' is already registered. They will be notified of their invitation via email.');
                }
        });

}

function showImage(){
        document.getElementById('overlay').style.visibility='visible';
    }
document.getElementById('.videofullme').style['-webkit-transform'] = 'rotate(90deg)';
document.getElementById('.videofullme').style.webkitTransform = 'rotate(90deg)';
document.getElementById('.videofullme').style.WebkitTransform = 'rotate(90deg)';
</code></pre>
