How to fix ReferenceError: Can't find variable: jQuery/$

I know, there are a lot of questions like this, but they doesn't help me.

My situation is following.

1. I copy one (working) site with some changes to create another.


2. After I did it with not so much changes javascript on new site doesn't work, saying "ReferenceError: Can't find variable: jQuery" and "ReferenceError: Can't find variable: $".


3. 
   

   I added into the code alerts:

   
   

   
   alert('aaa');
   var x=$('td[type="x"]').size();
   alert('aaa1');
   
   

and see "aaa" alert, but don't see "aaa".

4. 
   

   I've checked, like it is said here, with Safari's debugger that jquery files are found and loaded, I can see them in "Resources" tab.

   
   


5. 
   

   adding ready in the line doesn't help:

   
   

   
   alert('aaa');
   var x=$(document).ready($('td[type="x"]').size());
   alert('aaa1');
   
   

What else I can do about it?

I have OSX 10.10.3 and Safari 8.0.5.