$ is not a function - jQuery error

Question

I have the jQuery loaded fine, I've quadruple-checked, though I'm getting this error in FireBug "$ is not a function" and my code doesn't work.

Here's my code:

<script type="text/javascript">
    $("ol li:nth-child(1)").addClass('olli1');
    $("ol li:nth-child(2)").addClass("olli2");
    $("ol li:nth-child(3)").addClass("olli3");
    $("ol li:nth-child(4)").addClass("olli4");
    $("ol li:nth-child(5)").addClass("olli5");
    $("ol li:nth-child(6)").addClass("olli6");
    $("ol li:nth-child(7)").addClass("olli7");
    $("ol li:nth-child(8)").addClass("olli8");
    $("ol li:nth-child(9)").addClass("olli9");
    $("ol li:nth-child(10)").addClass("olli10");
    $("ol li:nth-child(11)").addClass("olli11");
    $("ol li:nth-child(12)").addClass("olli12");
    $("ol li:nth-child(13)").addClass("olli13");
    $("ol li:nth-child(14)").addClass("olli14");
    $("ol li:nth-child(15)").addClass("olli15");
    $("ol li:nth-child(16)").addClass("olli16");
    $("ol li:nth-child(17)").addClass("olli17");
    $("ol li:nth-child(18)").addClass("olli18");
    $("ol li:nth-child(19)").addClass("olli19");
    $("ol li:nth-child(20)").addClass("olli20"); 
</script>

Answer 1

As RPM1984 refers to, this is mostly likely caused by the fact that your script is loading before jQuery is loaded.

Answer 2

give us an adress

Answer 3

There are two possible reasons for that error:

1. your jquery script file referencing is not valid

2. try to put your jquery code in document.ready, like this:

   $(document).ready(function(){

   ....your code....

   });

cheers

Answer 4

That error kicks in when you have forgot to include the jQuery library in your page or there is conflict between libraries - for example you be using any other javascript library on your page.

Take a look at this for more info:

• Using jQuery with other libraries

Answer 5

When jQuery is not present you get $ is undefined and not your message.

Did you check if you don't have a variable called $ somewhere before your code?
Inspect the value of $ in firebug to see what it is.

Slightly out of the question, but I can't resist to write a shorter code to your class assignment:

    var i = 1;
    $("ol li").each(function(){
        $(this).addClass('olli' + i++);
    });

Answer 6

It's really hard to tell, but one of the 9001 ads on the page may be clobbering the $ object.

jQuery provides the global jQuery object (which is present on your page). You can do the following to "get" $ back:

jQuery(document).ready(function ($) {
    // Your code here
});

If you think you're having jQuery problems, please use the debug (non-production) versions of the library.

Also, it's probably not best to be editing a live site like that ...

Answer 7

In Wordpress jQuery.noConflict() is called on the jQuery file it includes (scroll to the bottom of the file it's including for jQuery to see this), which means $ doesn't work, but jQuery does, so your code should look like this:

<script type="text/javascript">
  jQuery(function($) {
    for(var i=0; i <= 20; i++) 
      $("ol li:nth-child(" + i + ")").addClass('olli' + i);
  });
</script>