.focus() with Zepto not working

Question

I am pretty new to JavaScript and js-libraries. I am using zepto.js and want to focus on an input field with $('input').focus(); after I am doing a submit (appending an element to a list). I used to work with jQuery but due to performance I am using Zepto now. The same code worked fine with jQuery. I found just few documentation on .focus() and .blur() in Zepto, but as I understood, it should work.

I also tried getElementById('input').focus(); but that didn't work aswell.

The whole code:

$(document).ready(function(){
    $('button').tap(function(){
        var toAdd = $('input[name=list-element]').val();
        if (toAdd == ''){
            return false;
        }
        else {
            $('#liste').append('<div class="item item-red">' + toAdd + '</div>');
        };
        $('input').val('');
        $('input').focus();
        });

Answer 1

Found a solution myself:

I deleted $('input').focus(); in the script.js and added the following script directly in the HTML file:

<script type="text/javascript">
          function focus(){
            document.inputform.list-element.focus();
          };
</script>

And edited the button-tag: <button onclick="focus()">GO ▼</button>