Help me to understand these codes!?

[newbe123]

I'm totally new when it comes to JavaScript and I'm trying to learn new things. Here I found the codes I tried it and it works but I would like to have comments for the code to understand how they have proceeded.
can someone help me and explain these codes with comments?
I really appreciate it.

var config = {
    "tags": "vfx+compositing",
    "user": "andreasl",
    "scriptTagTarget": "scriptTagDiv",
    "deliciousTarget": "deliciousLinks",
    "callbackFunction": "fetchDelicious"
};

window.onload = function() {
    var url = 'http://feeds.delicious.com/v2/json/' + config.user + '/' + config.tags + '?callback=' + config.callbackFunction;
    var scriptDiv = document.getElementById(config.scriptTagTarget);
    addScriptTag(url, scriptDiv);
};



function addScriptTag(url, scriptDiv) {

    if (scriptDiv.hasChildNodes())
    {
        scriptDiv.removeChild(scriptDiv.firstChild)
    };

    var scriptElement = document.createElement('script');
    scriptElement.setAttribute('src', url);
    scriptDiv.appendChild(scriptElement);
}


function fetchDelicious(json) {
	var html = "";
	for (var i = 0; i < json.length; i++) {
		var uri = json[i].u;
		var description = json[i].d;
		var tags = json[i].t; //array
		var time = json[i].dt; 
		//var n = json[i].n; //new?
		var author = json[i].a;
		var bHtml = "<li><a href=\":u\">:d</a>:t</li>".replace(":u", uri).replace(":d", description); 
		var tagHtml = ""; 
		for(var n = 0; n < tags.length; n++)  { 
		tagHtml += "<li><a href=\"http://delicious.com/:u\">:d</a></li>".replace(":u", [author,tags[n]].join("/")).replace(":d", tags[n]); 
		}
		tagHtml = "<ul>" + tagHtml + "</ul>";
		html += bHtml.replace(":t", tagHtml); 
	}
	html = "<ul>" + html + "</ul>"; 
	document.getElementById(config.deliciousTarget).innerHTML = html;
   

}

[Nile]

var config = {
    "tags": "vfx+compositing",
    "user": "andreasl",
    "scriptTagTarget": "scriptTagDiv",
    "deliciousTarget": "deliciousLinks",
    "callbackFunction": "fetchDelicious"
}; //array, tags = vfx+compositing, user = andreasl, scriptTagTarget = scriptTagDiv, etc..

window.onload = function() { //when the page loads
    var url = 'http://feeds.delicious.com/v2/json/' + config.user + '/' + config.tags + '?callback=' + config.callbackFunction; //set a variable to the value of feeds.delicious.com/v2/json/user/tags?callback=callbackFunction
    var scriptDiv = document.getElementById(config.scriptTagTarget); //get the target div 'scriptTagDiv'
    addScriptTag(url, scriptDiv); //custom function addScripTag with url and scriptdiv - so I'm assuming its put something from the url int he variable url and display it in script div
};



function addScriptTag(url, scriptDiv) { //custom function

    if (scriptDiv.hasChildNodes())
    {
        scriptDiv.removeChild(scriptDiv.firstChild) //if it has children, get rid of the first one
    };

    var scriptElement = document.createElement('script'); //make a script tag
    scriptElement.setAttribute('src', url); //set the src = url(on delicious)
    scriptDiv.appendChild(scriptElement); //add the <script type="text/javascript" url="feeds.delicious.com/v2/etc" /> to your page, so the script is applied to your page
}


function fetchDelicious(json) { //custom function using json probably
	var html = "";
	for (var i = 0; i < json.length; i++) { //the following is getting things such as the descritiptopn, tags, and replacing some things from the javascript file and displaying them on the page
		var uri = json[i].u;
		var description = json[i].d;
		var tags = json[i].t; //array
		var time = json[i].dt; 
		//var n = json[i].n; //new?
		var author = json[i].a;
		var bHtml = "<li><a href=\":u\">:d</a>:t</li>".replace(":u", uri).replace(":d", description); 
		var tagHtml = ""; 
		for(var n = 0; n < tags.length; n++)  { 
		tagHtml += "<li><a href=\"http://delicious.com/:u\">:d</a></li>".replace(":u", [author,tags[n]].join("/")).replace(":d", tags[n]); 
		}
		tagHtml = "<ul>" + tagHtml + "</ul>";
		html += bHtml.replace(":t", tagHtml); 
	}
	html = "<ul>" + html + "</ul>"; 
	document.getElementById(config.deliciousTarget).innerHTML = html;
   

}

[newbe123]

Thank you so much

[Nile]

No problem, I'm glad to help

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