render.html

{% extends "index.html" %}
{% block charts %}
  {% for c in charts %}
    <div id="{{ c['id']}}"></div>
  {% endfor %}
  <script type="text/javascript">
    var charts = {{ charts }}
  </script>
  <script src="{{ url_for('static', filename='render_charts.js') }}"></script>
{% endblock %}

render_charts.js

$(document).ready(function() {
  $.each(charts, function(index, chart){
    $('#'+chart['id']).highcharts(chart);
  })
});

views.py

@app.route('/render/')
def render_charts():
  try:
    charts = [{'chart_id': c['id'], 'chart': get_json(c['id'])
    for c in dict(request.args)]
    return render_template('render.html', charts=charts)
  except KeyError as e:
    abort(400)
    
def get_json(c):
  with open(os.path.join(app.root_path, app.config['JSON'], c['id'], '.json'),'r') as j:
    return j