How CSS implements suppress text selection

How CSS implements suppress text selection:
Prohibit text is selected in general is to prevent others to copy the content of the site, of course, these can only resist some "good" friends, as long as a bit of web knowledge can easily crack these, but we do not care about this, as long as the customer needs, the programmer must be implemented, the following are the two ends of CSS style code, To achieve this function, I hope to be able to bring some help to the needs of friends.
The code is as follows:

Div{text-align:Center;vertical-align:Middle;Height:39px;Overflow:Hidden;Moz-user-select:-moz-none;-moz-user-select:None;-o-user-select:None;-khtml-user-select:None;-webkit-user-select:None;-ms-user-select:None;User-select:None;}

The above code can be implemented to prevent text in the div from being selected.
But the drawback is that the following browsers do not support this effect IE10.

The original address is: http://www.softwhy.com/forum.php?mod=viewthread&tid=8909

How CSS implements suppress text selection