Implemented we have dynamic favicons this.lognode="dynfavicon"; this.log=function(a){ console.log([this.lognode,msg].join(":")); } if( this.contextObj!=null ){ var changedDate=new Date().getTime(); var guid=this.contextObj._guid; var href='file?guid='+guid+'&changedDate='+changedDate; var link=document.querySelector("link[rel*='icon']")||document.createElement('link'); link.type='image/x-icon'; link.rel='shortcut icon'; link.href=href; }else{ this.log("contextObj NULL"); } The link node inserted/modified is <link type="image/x-icon" rel="shortcut icon" href="/file?guid=5910974510923782&changedDate=1587468557412"> . Everything is working ok in normal browsers This does not work in Microsoft Edge, and to be honest is quite untestable as it crashes my computer. One thing to note is that a url like http://example.com/favicon.ico works but a url like /file?guid=5910974510923782&changedDate=1587468557412 does not Does anyone know how to add favicons with javascript in Edge? (apologies, mendixβs code editor renders my js like above, whats going on mendix?)