Blackboard JS Hack to force rewrite copied URLs that link to shell-specific locations

ContentReplace.js

<!-- This snippet binds a function to the "dom:loaded" event.
You can put your own javascript into the function, or replace
the entire snippet. -->
<script type="text/javascript">
    Event.observe(document,"dom:loaded", function() {
        //Just filter by span since BB uses random hashes for class names
        let elements = document.getElementsByTagName('span');
       
        let matching = "None";
        for (let i = 0; i < elements.length; i++) {
            //iterate EVERY span looking for Course Content, because Blackboard.
            if (elements[i].title === 'Course Content' ) {
                //found the correct content
                matching = elements[i];
            }
        }
		
		//Should check that `matching` is filled here for safety, but in our case it ALWAYS will be found 
                
        //isolate the content_id portion to extract the proper content_id to use for replacement
        const urlref = matching.parentElement.attributes[0].nodeValue;
        const firstSubIndex = urlref.indexOf('content_id=');
        const secondSubIndex = urlref.indexOf("&");
		
        // "content_id=" is 11 characters long and some people hate magic numbers
		const contentIDToIgnoreSize = 11;
        const finalID = urlref.substring(firstSubIndex + contentIDToIgnoreSize, secondSubIndex);        
        
        //replacing img text
        
        //again grab and iterate every single img because there's no better way provided via Blackboard.
        elements = document.getElementsByTagName('img');
        for (let i = 0; i < elements.length; i++) {
            if (elements[i].title === 'Course Content' ) {
                
                //need the parent of the img itself, as that's where the link URL actually lives
                let mainElement = elements[i].parentElement;
                //The actual URL to be manipulated
                matching = mainElement.attributes[0].nodeValue;
                              
                //replace the copied incorrect content ID with the one found previously
                matching = matching.replace(/content_id=([^&]*)/, "/content_id=" + finalID);
               
                //Update BB's link to match
                mainElement.attributes[0].nodeValue = matching;
               //chug beers
            }
        }
    });
</script>