// JavaScript Document

function pgall(whichpic) {
	
var source = whichpic.getAttribute("href"); 
var placeholder = document.getElementById("placeholder");
placeholder.setAttribute("src", source); //change the source of the image 

//whichpic is an element node. 
//We can extract the path to the image by using the getAttribut method on the whichpic element.By passing href as the argument i can find out what the path is

//We need to update the src of the placeholder element, so we set the src attribute and the path we want the source to have.
}