improved index page: anchors now have hrefs

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

de.srsoftware.cal.web/src/main/resources/script/index.js

@@ -8,6 +8,7 @@ function addCell(row,content,id){
     var a = document.createElement('a');
     if (content){
         a.onclick = e => showOverlay('/static/event?id='+id);
+        a.href = '/static/event?id='+id;
         a.innerHTML = content;
     }
     row.insertCell().appendChild(a);
@@ -155,6 +156,7 @@ function showOverlay(url){
     closeBtn.innerHTML = '✖';
     closeBtn.title = 'close overlay';
     div.appendChild(closeBtn);
+    return false;
 }
 
 // adds or removes tag from set, updates shown tags