I made a fiddle here : http://jsfiddle.net/csanonymus/kQAXC/
I used plain JS like this :
var startGame=document.getElementById('start_button');
var min=1;
var max=400;
var board=document.getElementById('game_board');
var i=1;
startGame.onclick=function(){
var newItem = document.createElement('input');
newItem.type="button";
newItem.style.position="absolute";
newItem.value="test"+i;
i++;
newItem.style.left=Math.floor(Math.random() * (max - min) + min) + "px";
newItem.style.top=Math.floor(Math.random() * (max - min) + min) + "px";
board.appendChild(newItem);
}