HTML anchor tag with Javascript onclick event
If your onclick function returns false the default browser behaviour is cancelled. As such:
<a href='http://www.google.com' onclick='return check()'>check</a><script type='text/javascript'>function check(){ return false;}</script>Either way, whether google does it or not isn't of much importance. It's cleaner to bind your onclick functions within javascript - this way you separate your HTML from other code.
You can even try below option:
<a href="javascript:show_more_menu();">More >>></a>
From what I understand you do not want to redirect when the link is clicked.You can do :
<a href='javascript:;' onclick='show_more_menu();'>More ></a>