Zotero Better Bibtex - Postscript to format access date (long format) and url fields on webpage items and setting month field as a number on any item.

better_bibtext_postscript.js

if (Translator.BetterBibTeX) {
    if (tex.has.month) {
        tex.add({ name: 'month', value: tex.date.month});
    }
    if (zotero.itemType === 'webpage') {
        if (zotero.accessDate) {
            var customDate = new Date(zotero.accessDate.replace(/\s*T?\d+:\d+:\d+.*/, ''));
            var intlCustomDate = new Intl.DateTimeFormat('en-GB', {year: 'numeric', month: 'long', day: 'numeric'}).format(customDate);
            tex.add({ name: 'note', value: "(accessed on " + intlCustomDate + ")" });
        }
        if (zotero.url) {
            tex.add({ name: 'howpublished', bibtex: "{Available online: \\url{" + tex.enc_verbatim({value: zotero.url}) + "}}" });
        }
    }
}