Javascript : Uncheck a different checkbox when one checkbox is Unchecked

I know its kinda duplicate , my am trying to do this in a different way and thus re-posting this question.

What am trying to achieve is , when someone "Un-Check" the OSPF Checkbox .. the Passive Interface Check should also get "Uncheched" automatically. I'm trying to debug why UnChecked is not working, but no luck. Below is my code.

OSPF <input type="checkbox" name="ospfen" id="ospfen_1" onclick="if(this.unchecked){document.getElementById('ospfpassive_1').checked=false;}">&nbsp; Passive Interface<input type="checkbox" name="ospfpassive" id="ospfpassive_1" onclick="if(this.checked){document.getElementById('ospfen_1').checked=true;}"> <br />

I also wanted if someone check the Passive Interface checkbox...the OSPF should get checked and this part of the code is working fine. Only "Un-Check" is not working.

Thanks in advance