The user-select CSS property controls whether the user can select text. This doesn't have any effect on content loaded as part of a browser's user interface (its chrome), except in textboxes.

テキストのドラッグを停止

user-drag

style="user-select: none;"
user-drag: none;

User select is specific to text as mentioned in User Select - MDN web Docs by default, user-select is enable to texts. To disable that property use the below-mentioned CSS stylings.
-moz-user-select: none;
-webkit-user-select: none;
-ms-user-select: none;
user-select: none;
User Drag is generic, that can be applied to div, image, p, etc.,

<p draggable="true">Contents</p> //Enable dragging
<img src="image.jpg" draggable="false" alt="can't be dragged"></img> //Disable dragging

user-selectはtextに限られ、user-dragはdom elemのdragに適用されます.