Your first attempt failed because it was a CSS property and not an attribute (part of the style attribute).
Your second attempt failed because for some off reason, when making this API casing-like-this gets converted to camelCasingLikeThis . This is likely because the folks who built JavaScript and the folks who built CSS weren’t very well coordinated.
The following should work:
document.getElementById("div").style.pointerEvents = "none";