echo $html->link("Dashboard",
     "/dashboard/index",
     array("onmouseover" => "Tip('Test');") );

<a href="/dashboard/index" onmouseover="Tip(&#039;Test&#039;);">Dashboard</a>

echo $html->link('Dashboard', '/dashboard/index',
array("onmouseover" => "Tip('Test');"), null, false);

echo $html->link("Dashboard",
     "/dashboard/index",
     array("onmouseover" => "Tip('Test');"),
     array('escape' => false));