Minor bug fixes and code formatting, and limit-years style modified a little bit
diff --git a/js/limit-years.js b/js/limit-years.js
index cbbef95..41647f7 100644
--- a/js/limit-years.js
+++ b/js/limit-years.js
@@ -1,7 +1,5 @@
 // *********** HERE STARTS limit-years.js *************

 

-window.addEventListener("load", addYearList);

-

 var limitYears = false;

 var showYears = new Set();

 

@@ -9,10 +7,10 @@
 	//targetYear: graf.nodes[e.source].year,

 	if(limitYears) {

 		var added = new Set();

-		

+

 		s.graph.nodes().forEach(function(n) {

 			var numNeig = s.graph.numNeighborsFromYears(n.id, showYears);

-			

+

 			if ((n.year == 0 && (n.sex == 'F' || n.sex == 'M') )

 					|| numNeig == 0

 					|| (!showYears.has("" + n.year) && (n.year != 0) )) {

@@ -23,19 +21,19 @@
 				added.add(n.id);

 			}

 		});

-		

+

 		s.graph.edges().forEach(function(e) {

 			if(!added.has(e.source) && !added.has(e.target)){

 				e.hidden = true;

 			}

 			else e.hidden = false;

-		}); 

+		});

 	}

 	else {

 		s.graph.nodes().forEach(function(n) {

 			n.hidden = false;

 		});

-		

+

 		s.graph.edges().forEach(function(e) {

 			e.hidden = false;

 		});

@@ -44,7 +42,7 @@
 

 function altYearList() {

 	var yearlist = document.querySelector("#year-list");

-	

+

 	if(yearlist.style.display == "none"){

 		yearlist.style.display = "block";

 		document.querySelector("#settings i").innerText = "close";

@@ -57,37 +55,42 @@
 	}

 }

 

-function addYearList() {	

+function addYearList() {

 	var ylistspan = document.querySelector("#year-list-span")

-	for(var year=2006; year<2019; year++) {

+	for(var year = 2006; year < 2019; year++) {

+		var lab = document.createElement("label");

+		lab.setAttribute("class", "mdl-checkbox mdl-js-checkbox mdl-js-ripple-effect custom-checkbox");

+		lab.setAttribute("for", "checkbox-"+year);

 		var yin = document.createElement("input");

 		yin.type = "checkbox";

-		yin.class = "mdl-button mdl-js-button mdl-button--fab mdl-button--mini-fab mdl-js-ripple-effect mdl-button--colored";

-		yin.name = "" + year;

-		yin.addEventListener("change", function(){ 

+		yin.setAttribute("class", "mdl-checkbox__input");

+		yin.name = year;

+		yin.id = "checkbox-"+year;

+		yin.addEventListener("change", function() {

 			limitYears = true;

-			

+

 			if(this.checked) {

 				showYears.add(this.name);

-			}

-			else {

+			} else {

 				showYears.delete(this.name);

 			}

-			

-			if(showYears.size == 0) limitYears = false;

-			

+

+			if (showYears.size == 0) limitYears = false;

+

 			repaint();

-			

+

 			s.refresh();

 		});

-		

-		var lab = document.createElement("label");

-		lab.innerHTML = "" + year + "<br>";

-		

-		ylistspan.appendChild(yin);

+

+		var span = document.createElement("span");

+		span.innerText = year;

+		span.setAttribute("class", "mdl-checkbox__label");

+

+		lab.appendChild(yin);

+		lab.appendChild(span);

 		ylistspan.appendChild(lab);

+		ylistspan.insertAdjacentHTML("beforeend", "<br>");

 	}

-	

+

 	document.querySelector("#settings").addEventListener("click", altYearList);

 }

-