Found following error message consol:
Error: script5007 unable to get value of the property 'parentnode': object is null or undefined
svg.js, line 1 character 21336
This refers to "svgweb.removeChild(removeMe,removeMe.parentNode)"
Attached screen shot (with Dutch error message, but you find English translation above)
That code is unchanged from the original firmware, and is pretty much impossible to debug since Asus has obfuscated it by removing any whitespace from the script.