Bootstrap 3 Skeleton

This is a simple Bootstrap skeleton. You can fork it to get a ready to use Bootstrap fiddle.

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/2.1.0/bootstrap.min.js"></script>
<div class="container">    
<div class="row">
        <div class="col-xs-3">
            <label for="input_string">Enter Numbers</label>
        </div>
        <div class="col-xs-9">
            <input type="text" class="form-control" name="input_string" id="input_string" />
        </div>
    </div>
<div class="row">
        <div class="col-xs-3">
            &nbsp;
        </div>
        <div class="col-xs-9">
            <input type="button" class="btn btn-default" name="get_answer" id="get_answer" value="Submit" onclick="javascript:findSum()" />
        </div>
</div>    
    </div>

CSS

@import url('http://getbootstrap.com/dist/css/bootstrap.css');
@import url('http://netdna.bootstrapcdn.com/bootstrap/3.0.3/css/bootstrap-theme.min.css');

JavaScript

function findSum() {
    var input = document.querySelector('#input_string').value;
    if(!(input.match(/\d+/))) {
        alert("Only digits please");
        return;
    }
    // program
    sum = input.toString().split("").reduce(function(i,j,key,value) {ni = Number(i);nj = Number(j);return ni+nj})
    alert("Sum of input numbers is " + sum);
}