Select2() is not a function

So i have downloaded select2 i have “installed it” by putting it into my folder and then loaded it on my site when i check the console (where i can see all of the scripts being loaded) i can see the file select2.js

I went to their documentation and copied it and added $("#e9").select2();

However when i load the page i get the following error:

TypeError: $(...).select2 is not a function


$("#e9").select2();

Have anyone else experianced anything like this?

Additional information here is my script:

    jQuery(document).ready(function(){
    var max_amount = parseFloat($('#max_amount').val());
    $( "#item_amount" ).keyup(function() {
           if($(this).val() > max_amount){
            $(this).val( max_amount);
        }
        if( /D/.test($(this).val()) ){
            alert('Må kun indeholde tal!');
            $(this).val('');
        }
        if($(this).val()== '0'){
            alert('Må ikke være 0!');
            $(this).val('');
        }
    });
    $("#e1").select2();

});
function addToBasket(){
    var amount = $('#item_amount').val();
    if(amount == ""){
        amount = 1;
    }

    if(amount > 0){
    $.ajax({
        type: 'POST',
        url: myBaseUrl + 'Products/addItemToBasket',
        dataType: 'json',
        data: {
            id: window.location.pathname.substring(window.location.pathname.lastIndexOf('/') + 1),
            amount: amount
        },
        success: function (data) {
            var urlToBasket = myBaseUrl+'Products/basket';
            var newAmount = parseInt(amount)
            var price = data[0]['Product']['pris'];
            var id = data[0]['Product']['id'];
            var dat = data;
            var tmp_basket_html = $('#basket_amount').html();
           if($('#basket_amount').html() !== " Tom"){
              $('#shopping_table_body').append(
                  "<tr id='"+id+"'>" +
                      "<td class='image'>" +
                      ""+
                      "</td>" +
                      "<td class='name'>" +
                      " "+data[0]['Product']['name'] +
                      "</td>"+
                      "<td class='quantity'>" +
                      "x "+amount +""+
                      "</td>"+
                      "<td class='total'>" +
                      ""+price*amount+
                      "</td>" +
                      ""+
                      "<td class='remove'>" +
                      "<input class='icon-remove' type='button' onclick='removeItemFromBasket("+id+")'>"+
                      "</td>"+
                      "</tr>"
              );
           }else{
               $("#shopping_menu").append(
                   "<ul class='dropdown-menu topcartopen'>"+
                       "<li id='basket_list'>"+
                      "<table id='shopping_table'>"+
                        "<tbody id='shopping_table_body'>"+
                       "<tr id='"+id+"'>" +
                       "<td class='image'>" +
                       ""+
                       "</td>" +
                       "<td class='name'>" +
                       " "+data[0]['Product']['name'] +
                       "</td>"+
                       "<td class='quantity'>" +
                       "x "+amount +""+
                       "</td>"+
                       "<td class='total'>" +
                       ""+price*amount+
                       "</td>" +
                       ""+
                       "<td class='remove'>" +
                       "<input class='icon-remove' type='button' onclick='removeItemFromBasket("+id+")'>"+
                       "</td>"+
                       "</tr>"+
                       "</table>"+
                       "</li>"+
                       "<div class='well pull-right'>"+
                       "<input type='button' onclick='goToBasket()' class='btn btn-success' value='Tjek ud'>"+
                       "</div>"+
                       "</ul>"

               )
           }
            updateTotal(amount,price);
            updateBasketAmount();
        }
    });
    }
    Notifier.success('Vare tilføjet', 'Tilføjet'); // text and title are both optional.
}
function updateTotal(amount, price){
    var price = parseFloat(price);
    var oldValue = parseFloat($('#basket_total_cost').html());
    var newPrice = amount*price+oldValue;
    $('#basket_total_cost').html(newPrice);
}
function updateBasketAmount(){
   var tmp =  $('#basket_amount').html();
    if(!isNaN(tmp)){
   var oldAmount = parseInt(tmp.substr(0,2));
    var i = oldAmount + 1;;
    $('#basket_amount').html(
        ""+i+" vare(r)"
    );
    }else{
        $('#basket_amount').html(
            "1"+" vare(r)"
        );
    }
}
function goToBasket(){
    window.location.href = myBaseUrl+'Products/basket';
}

Answer

I was having this problem when I started using select2 with XCrud. I solved it by disabling XCrud from loading JQuery, it was it a second time, and loading it below the body tag. So make sure JQuery isn’t getting loaded twice on your page.