container = function(captionText, width_over) {
const div=DOM.element('div')
div.setAttribute("class","border m-2 p-2")
div.setAttribute("style",`width: ${width_over?width_over:(width>800?800:width)}px`)
if (captionText) {
const caption=DOM.element('figcaption')
caption.setAttribute("style","max-width:100%")
caption.append(captionText)
div.append(caption)
}
return div
}