How to loop through the alphabet via underscoreJS

var alphabet = "abcdefghijklmnopqrstuvwxyz".split("");
_.each(alphabet, function(letter) {
  console.log(letter);
});

That's how you could do it.

1. Create a range with the charcodes

   var alphas = _.range(
       'a'.charCodeAt(0),
       'z'.charCodeAt(0)+1
   ); 
   // [97 .. 122]
   

2. Create an array with the letters

   var letters = _.map(alphas, a => String.fromCharCode(a));
   // see @deefour comment
   
   // Non ES6 version
   // var letters = _.map(alphas, function(a) {
   //    return String.fromCharCode(a);
   // });
   
   // [a .. z]
   

3. Inject into your template

   var tpl = 
   '<ul>'+
       '<% _.each(letters, function(letter) { %>'+
           '<li><%= letter %></li>'+
       '<% }); %>'+
   '</ul>';
   var compiled = _.template(tpl);
   var html = compiled({letters : letters});
   

And a demo http://jsfiddle.net/hPdSQ/17/

var alphas = _.range(
    'a'.charCodeAt(0),
    'z'.charCodeAt(0)+1
); 

var letters = _.map(alphas, a => String.fromCharCode(a));

var tpl = 
'<ul>'+
    '<% _.each(letters, function(letter) { %>'+
        '<li><%= letter %></li>'+
    '<% }); %>'+
'</ul>';
var compiled = _.template(tpl);

var html = compiled({letters : letters});

document.getElementById('res').innerHTML = html;

<script src="http://underscorejs.org/underscore-min.js"></script>
<div id='res'></div>