Certain Javascript works on single pages, but not when loaded globally via a Drupal theme's javascript

Question

On the SO-chat, I was advised to ask the following question here:

I would like to load some Javascript globally on my complete website, via a Drupal theme's Javascript; insead of having to re-insert the Javascript-code each article over and over again.

For example, I have managed this with the following code (imagine it wrapped in <script type="text/javascript">...</script>, when inserted locally):

(which worked fine both locally when inserted per page, and also when loaded in to the Drupal theme's javascript globally as such):

(function ($) {
    $(document).ready(function () {
        $
        $(".toggler").click(function () {
            $(this).next().slideToggle("slow");
        }).next().hide();
        $("a[href^=#]").click(function () {
            var id = $(this).attr('href');
            $(id).parents('.toggled').fadeIn("fast");
        });
    });
})(jQuery)

However, for 2 other pieces of Javascript, I can't get things to work when loading them globally. However, they work great when inserted locally in to each consecutive article, as such (I'll mention just 1 smaller code, for reference):

(imagine it wrapped in <script type="text/javascript">...</script> again, when inserted locally):

(function($) {
    $(document).ready(function() {
        function getKey(element) {
            return element.href;
        }

        function sameGroupAs(element) {
            var key = getKey(element);
            return function() {
                return getKey(this) === key;
            }
        }
        $(document).on("mouseenter", "a", function() {
            $("a").filter(sameGroupAs(this)).addClass(
                "active");
        }).on("mouseleave", "a", function() {
            $("a").filter(sameGroupAs(this)).removeClass(
                "active");
        });
    });
})(jQuery)

Just for reference: if you would be interested how I added the Javascript to a Drupal's theme.

Answer 1

The solution was simply to put every single "script" in a seperate .js-file. If they were put into one .js-file, they would simply all become dysfunctional.

Anyone knows whether this is a Drupal-specific strategy, or whether this is general to Javascript and known to everyone in "the field"?