Javascript: Calculate width of div as sum of images

Basically, I need "style="width:__" to be added to the "img-container' div, with the width being the sum of all the images and their padding. The images and image widths are added in dynamically through a CMS, which is why I need the javascript to calculate the width dynamically.

<div id='img-container'[HERE IS WHERE I NEED THE WIDTH TO BE ADDED]>
 <div class='picture_holder' >
 <div class='picture' >
 <img src="{image}" style='width:{width}px;padding-right:10px;'/>
 <div class='captioning'>{caption}</div>
 </div>
 </div>
 </div>
 

I don't know javascript at all, but tried to piece something together (I didn't even get to adding in the padding yet):

<script type="text/javascript">
 var $name = ('div#img-container');
 var Imgs = div.getElementsByTagName('img');
 var w = 0;
 for ( var i = 0; i < Imgs.length; i++ ){
     w += parseInt(Imgs[i].offsetWidth);
 }
 </script>
 

It's obviously not working at all though. Any help would be much appreciated!

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