WebGL ExternalCall screenshot works in Safari and firefox, but not chrome

Hello, I am hoping that someone can help me figure out why this ExternalCall code works for encoding a png screenshot within safari and firefox but results in a unspecified "network error" when used in chrome. or could provide me with a workaround that would work in all 3 browsers.

Thanks!

 <script type="text/javascript">
 function Download(data,name){
 var Download = {
 click : function(node) {
 var ev = document.createEvent("MouseEvents");
 ev.initMouseEvent("click", true, false, self, 0, 0, 0, 0, 0, false, false, false, false, 0, null);
 return node.dispatchEvent(ev);
 },
 encode : function(data) {
 return 'data:image/png;base64,' + data ;
 },
 link : function(data, name){
 var a = document.createElement('a');
 a.download = name ||
 self.location.pathname.slice(self.location.pathname.lastIndexOf('/')+1);
 a.href = data || self.location.href;
 return a;
 }
 };
 Download.save = function(data, name){
 this.click(
 this.link( this.encode( data ), name ) ); };
 console.log(data);
 var img=document.createElement("img");
 img.alt= name;
 img.src= Download.encode(data);
 img.href = Download.save(data,name);
 }
 
   </script>

the data being passed into it is a System.Convert.ToBase64String() of an byte[] that is equal to the Texture2D.EncodeToPNG() being read from the camera for the screenshot.