funTrick.js

function dfs(depth, x, y){
        if(depth == 5)return false;
        var div = document.createElement('div');
		div.style.position = 'absolute';
		div.style.left = (x + 100)+'px';
		div.style.top = (y + 100)+'px';
		div.style.width = (depth * 10)+'px';
		div.style.height = (depth * 10)+'px';
		div.style.padding = '10px';
		div.style.background = '#eee';
		
		document.body.appendChild(div);
        dfs(depth+1,x,y);
		console.log(depth,x,y);
    }
    
    document.onmousemove = function(e){
    	dfs(1,e.pageX,e.pageY);
    }