parseint
An ES-spec-compliant `parseInt` shim/polyfill/replacement that works as far down as ES3
number.issafeinteger
An ES-spec-compliant Number.isSafeInteger shim/polyfill/replacement that works as far down as ES3
number.isinteger
An ES-spec-compliant Number.isInteger shim/polyfill/replacement that works as far down as ES3