I try to display a span when the cursor of the mouse is on a help icon.
It works, but nevertheless, I don\'t manage to remove the border around the icon.
My
Try this:
img{border:0;}
You can also limitate the scope and only remove border on some images by doing so:
.myClass img{border:0;}
More information about the border css property can by found here.
Edit: Changed border from 0px to 0. As explained in comments, px is redundant for a unit of 0.
0px
0
px