In the newer browsers, you can distinguish the Shift-click event from a simple click, and disable the default response for Shift-click.
To disable Shift-click, insert the following code in your page’s <HEAD>
section:
<script language="JavaScript"> function mouseDown(e) { let shiftPressed=0; if (document.layers) { shiftPressed=(e.modifiers-0>3); } else { shiftPressed=e.shiftKey; } if (shiftPressed) { return false; } return true; } document.onmousedown = mouseDown; <script>