How to Settimeout to display multiple divs with if function in Javascript

So I have a simple javascript that looks like this

function  myfunction(){

var a = [document.getElementById("div1"),
document.getElementById("div2"), document.getElementById("div3")];

if(a.style.display=="none"){

setTimeout(function(){a.style.display="block";},4000);
}

}

And html code looks like this

<  a href="#" onclick="myfunction();"  >   click to show div1 and div2 after 4 seconds<   /a  >

<  p id="div1"   style="display:none;" >divv1<  /p  >


<  p id="div2"    style="display:none;"    >divv2<  /p  >



<  p id="div3"    style="display:none;"    >divv3<  /p  >

However divs are not showing after 4 seconds after I clicked.

Is there something wrong with my code?

Can someone please guide me further?

Thanks alot!