Javascript: mouse drag a small div1 hover over a large div2, how to let the big div2 trigger the mouse hover event

drag a small div1 to hover over a large div2.
how to let a large div2 trigger a mouse hover event
Oct.19,2021

I have done a lot of drag-related functions myself, although there are drag-related api, but customization and compatibility issues, I still like to write it myself. Let me tell you according to my idea:

1.  div1  mousedown 
2.  mousedown  document  mousemove  document  body  document  document  mouseup  mouseup mousemove 
3.  document  mousemove  position  fixed 
4.  mousedown  div2  mouseenter  mouserleave  div1  div2  document  document  mousemove 

what is the mouse hover event? you can listen to events such as mousemove when you hover while dragging.

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