Do you want to remove those characters or split on those characters to form an array? Your question is confusing and you should consider re-phrasing it.
If you want to remove them:
console.log("{99}".replace(/[{}]/g, "")) /* "99" */
If you want to split on them:
console.log("{99}".split(/[{}]/g)) /* ["", "99", ""] */
solved Javascript how to split() multiple string or values? [closed]