How can I auto hide alert box after it showing it? [duplicate]

All I want to do is, how can I auto hide alert box within specific seconds after showing it?

All I know is,

setTimeout(function() { 
      alert('close'); 
}, 5000);

// This will appear alert after 5 seconds

No need for this I want to disappear alert after showing it within seconds.

Needed scenario :

1. Show alert

2. Hide/terminate alert within 2 seconds

tldr; jsFiddle Demo

This functionality is not possible with an alert. However, you could use a div

function tempAlert(msg,duration)
{
 var el = document.createElement("div");
 el.setAttribute("style","position:absolute;top:40%;left:20%;background-color:white;");
 el.innerHTML = msg;
 setTimeout(function(){
  el.parentNode.removeChild(el);
 },duration);
 document.body.appendChild(el);
}

Use this like this:

tempAlert("close",5000);

You can't close an alert box with Javascript.

You could, however, use a window instead:

var w = window.open('','','width=100,height=100')
w.document.write('Message')
w.focus()
setTimeout(function() {w.close();}, 5000)