var i, x; for (i=0; i<arr.length; i++) { x = arr[i]; alert('Hello,'+x+'!'); }

var i, x; for (i=arr.length-1;i>=0;i--) { x = arr[i]; alert('Hello,'+x+'!'); }

var x = 0; while(x<arr.length) { alert("Hello,"+arr[x]+"!"); x++; }

var x = arr.length-1; while(x>=0) { alert("Hello,"+arr[x]+"!"); x--; }