jquery: $ is undefined

3 comments

1. $ is an alias of the jQuery() function, which apparently missing in this case…

   One way is to do, between jQuery and your other scripts:

   <script type="text/javascript">
       var $ = jQuery;
   </script>
   

   It should work

2. As others have told you, this is due to jQuery.noConflict. You can use a Immediately-Invoked Function Expression to map the $ variable to jQuery and simply place your logic inside of the expression:

   (function($) {
       // $ is now the same as jQuery
   
       $('body').remove();
   })(jQuery);
   // ^^^^^^ we're passing this to the "function($)" call
   

3. It looks like jQuery is not bound to the $ variable (to avoid conflicts, probably).

   If you want to use the $ variable then you can create a scope wherein it will be bound to that variable:

   (function ($) {
       // Use $ in this scope
   }(jQuery));
   

   If all your code should run when the document is ready (which is usually how it is done) then you can also use the scope that jQuery creates for you:

   jQuery(function ($) {
       // Document ready, use $ in this scope...
   });
   

   You can also just add jQuery to a global $ variable. If you know for certain that only jQuery will be using that variable then it is probably fine.

   $ = jQuery;
   

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