Hi  Friends
I have a small doubt that is what is the use of “ id” in visual force pages and how to use ,when to use these “id ” in vf page

Ex:1  <apex:pageBlock id="theBlock">

Ex:2  <apex:pageBlockSection title="Information" id="et">

Hi Guys,

I have visualforce page with Custom Components in it. My requirement now is to display a hover text on a custom field(with other Custom Text Field) in each component individually. Can any one let me know if this is achievable? If Yes, does that work in Lightning version?