hello guys I have this script and I want to wait 10 seconds before display the hidden text

Thank you
Code:
<a onclick ="javascript:ShowHide('HiddenDiv')" href="javascript:;" >Show/Hide</a>

<div class="mid" id="HiddenDiv" style="DISPLAY: none" >
This text was hidden
</div>

<script language="JavaScript">
function ShowHide(divId)
{
if(document.getElementById(divId).style.display == 'none')
{
document.getElementById(divId).style.display='block';
}
else
{
document.getElementById(divId).style.display = 'none';
}
}
</script>