How to disable cut, copy and paste operation from website text

Sometimes we need to restrict cut, copy, paste for website. Below
example no body can not copy text from this page.

oncopy="return false" oncut="return false" onpaste="return false"  - this
code will be restrict cut, copy and paste
<div oncopy="return false" oncut="return false" onpaste="return false">  
   Lorem ipsum Lorem ipsum orem ipsum Lorem ipsum orem ipsum  
   Lorem ipsum Lorem ipsum orem ipsum Lorem ipsum orem ipsum  
   Lorem ipsum Lorem ipsum orem ipsum Lorem ipsum orem ipsum  
   Lorem ipsum Lorem ipsum orem ipsum Lorem ipsum orem ipsum  
   Lorem ipsum Lorem ipsum orem ipsum Lorem ipsum orem ipsum  
 </div>  

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