Why would someone want to set the display of an element to none?

Question

Would it be that the web designer wants to revise the content of such an element? If so, why not use an HTML comment? Can someone please provide some insight?

Answer 1

display:none most is used by javascript

you set for example element1 to display:none so that element isn't shown and then say html that when client clicked on an another element for example element 2 run a javascript finction that its duty is to changing element1 display property to for example inline
one sample of this code is in creating menus that client just sees menus titles but when clicks on a title its submenus appears and it can chose one

Answer 2

you might use display:none on some situations were you want the element to not be on the display for some condiction, and out of this condiction you want it displayed