mitmproxy/libpathod/templates/response_previewform.html

<form class="form-inline" method="GET" action="/response_preview">
    <input 
        style="width: 20em"
        id="spec"
        name="spec"
        class="input-medium search-query"
        value="{{spec}}"
        placeholder="code[msg]:[features]"
    >
    <input type="submit" class="btn" value="preview">
    {% if not nocraft %}
    <a href="#" id="submitspec" class="btn">go to</a>
    {% endif %}
</form>
<script>
    $(function(){
        {% if not nocraft %}
        $("#submitspec").click(function(){
            document.location = "{{craftanchor}}" + $("#spec").val()
        });
        {% endif %}
    });
</script>