1var array = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'.split('');
2for (var i = 0; i < array.length; i++) {
3 var str = '';
4 for (var j = 0; j <= i; j++) {
5 if (array[j] == 'E') str += '3';
6 else str += array[j];
7 }
8 document.querySelector('span').innerHTML = document.querySelector('span').innerHTML + str + '<br />';
9}