firebug jQuery undefined message in rails app

In rails app, I add the following line of code in application.js and I
get jQuery is not defined in firebug console.
In application.html.erb, I have the following:
<script type="text/javascript"
src="../javascripts/application.js"></script>
<script type="text/javascript"
src="../javascripts/jquery-1.4.2.js"></script>

and I installed jquery in public/javascripts

Any ideas what's going wrong? thanks for reply.

(function($) {

    var linksToInt = {
        "#pple": 0,
        "#serv": 1,
        "#sol": 2,
        "#dash": 3,
        "#adm": 4,
        "#inv": 5,
        "#stu": 6

    }

    /*
    links = document.getElementsByTagName("a");
    if(links.className.indexOf("div-link") > -1){
        links.onclick = function{
removeHash(this.getAttribute("href"));};
    }
    */

    $("a.div-link").click(function(){displayDiv($(this).attr("href"));});

    function displayDiv(id){
    var linkInt = linksToInt[id];
    on_btn_click(linkInt);
    }

    function on_btn_click(displayDiv){
        displayDiv != null ? null : this;

        switch(displayDiv){
            case 0:
                $(content).empty();
                $(displayDiv).show();
                break;
            case 1:
                $(content).empty();
                $(displayDiv).show();
                break;
            case 2:
                $(content).empty();
                $(displayDiv).show();
                break;
            case 3:
                $(content).empty();
                $(displayDiv).show();
                break;
            case 4:
                $(content).empty();
                $(displayDiv).show();
                break;
            case 5:
                $(content).empty();
                $(displayDiv).show();
                break;
            case 6:
                $(content).empty();
                $(displayDiv).show();
                break;
        }
    }

})(jQuery);

Does anyone have a step by step instruction on how to remove prototype
completely so jQuery works? The jRails plugin seems to make them work
together. I want to remove prototype as I will never use it.
Thanks

Actually stepcarousel.js which uses jquery is working in the application
so I don't think there is a conflict with prototype. However I still get
the error jquery is undefined.

John Merlino wrote:

Does anyone have a step by step instruction on how to remove prototype
completely so jQuery works?

Sure:
1. Remove public/javascripts/prototype.js.
2. There is no step 2.

The jRails plugin seems to make them work
together. I want to remove prototype as I will never use it.

Perhaps unwise. After some experimentation with both, I'm include to
believe that Prototype may be the better of the two. I want to play
with both a little more before I state that as fact, though.

Thanks

Best,

First, try:

"<script type="text/javascript"
src="/javascripts/application.js"></script>"

Instead of

"<script type="text/javascript"
src="../javascripts/application.js"></script>"

Else:

"javascript_include_tag :all"

You can set :recursive => true if you want Rails to search all
subdirectories of public/javascripts.