While not an HTML attribute, you can make text non-selectable using CSS, demonstrating how HTML and CSS work together to control web content presentation.
Source Code
.no-select {
-webkit-user-select: none; /* Safari */
-moz-user-select: none; /* Firefox */
-ms-user-select: none; /* IE 10+ and Edge */
user-select: none; /* Standard syntax */
}
This text cannot be selected.