Does Prototype.js have a simple way of returning an element's outer width?
ie: width + left/right padding + left/right border.
Like jQuery's .outerWidth()
Element.Layout can help you in this regard, Here is a full fiddle demonstrating the options
CODE FROM FIDDLE
var layout = $('d1').getLayout();
console.log('My Width : ' + layout.get('width') + 'px');
console.log('My Full Width : ' + layout.get('border-box-width') + 'px');