Token function, event listener

end function
Uncaught SyntaxError: Unexpected token 'function' line 478 column 5
[violation] Added non-passive event listener to a
scroll-blocking <some>event.Consider marking event
handler as 'passive' to make the page more redponsive
see <URL>
i dont know how to add this in prj with chrome 51
document.addEventListener('touchstart', handler, {capture: true});

wheel events is also affected
[my workaround]
Radiobutton1.onchange = function(){
//how to use listener below?
  var as
   as  = document.addEventListener('touchstart', handler, {capture: true});
End JavaScript   
but my workaround needs to alter a lot of code,so is unfeasible

open in chrome :
 function(Radiobutton1_onchange) {
     var returnValue = "";
'uncaught SyntaxError: Function statements require a function name

My front portion should be
Function Radiobutton1. Onclick()