I am trying to change a css with a javascript and somehow I get the error that the javascript is null. 
I kinda know its a minor mistake I am doing there but I cant find a way to solve it...

```
<div class="page-content">
{{ page.mixedcontent|raw }}
</div>
<button id="slideshow">Slideshow aktivieren</button>

{% if page.mixedcontent is empty %}
<div id="galleria">
    {% for foto in fotos %}
        <img style="display:none" src="{{ asset('UserUploadFiles/' ~ homepage ~ '/' ~ foto.path) }}" data-title="" data-description="{{ foto.description }}">
    {% endfor %}
</div>
{% else %}
<script>
document.getElementById("#galleria").style.width = "550px";
</script>
<div id="galleria">
    {% for foto in fotos %}
        <img style="display:none" src="{{ asset('UserUploadFiles/' ~ homepage ~ '/' ~ foto.path) }}" data-title="" data-description="{{ foto.description }}">
    {% endfor %}
</div>
{% endif %}

```