V8 SpiderMonkey JavaScriptCore Chakra Carakan Other
Desktop browsers Servers/runtimes Mobile
Feature name Current browser IE 8 IE 9 IE 10 IE 11 Edge 12 Edge 13 Edge 14 Edge 15 Edge 16 Edge 17 Preview FF 45 ESR FF 51 FF 52 ESR FF 53 FF 54 FF 55 FF 56 FF 57 FF 58 FF 59 Beta FF 60 Nightly OP 12.10 CH 56,
OP 43[1]		 CH 57,
OP 44[1]		 CH 58,
OP 45[1]		 CH 59,
OP 46[1]		 CH 60,
OP 47[1]		 CH 61,
OP 48[1]		 CH 62,
OP 49[1]		 CH 63,
OP 50[1]		 CH 64,
OP 51[1]		 CH 65,
OP 52[1]		 CH 66,
OP 53[1]		 SF 8 SF 9 SF 10 SF 10.1 SF 11 SF 11.1 SF TP WK PJS Node 0.10[2] Node 0.12[3] Node 4[3] Node >=6.5 <7[3] Node 7.0-7.5[3] Node >=7.6 <8[3] Node 8.0-8.2[3] Node >=8.3 <8.7[3] Node >=8.7 <9[3] DUK 2.0 DUK 2.1 DUK 2.2 AN 4.4 AN 4.4.3 iOS 8 iOS 9 iOS 10.0-10.2 iOS >=10.3 <11 iOS 11
§Intl object MDN (Mozilla Development Network) logo  0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 0/2 2/2 2/2 0/2 0/2 2/2 2/2 2/2
§exists on global No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§has prototype of Object No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§Intl.Collator MDN (Mozilla Development Network) logo  0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 3/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 0/4 4/4 4/4 0/4 0/4 3/4 4/4 4/4
§exists on intl object No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§creates new Collator instances No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§constructor called without new creates instances No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§accepts valid language tags No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes
§Intl.Collator.prototype.compare MDN (Mozilla Development Network) logo  0/1 0/1 0/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 0/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 0/1 0/1 1/1 1/1 1/1 1/1 1/1 1/1 0/1 0/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 0/1 0/1 0/1 1/1 1/1 0/1 0/1 1/1 1/1 1/1
§exists on Collator prototype No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§Intl.Collator.prototype.resolvedOptions MDN (Mozilla Development Network) logo  0/1 0/1 0/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 0/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 0/1 0/1 1/1 1/1 1/1 1/1 1/1 1/1 0/1 0/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 0/1 0/1 0/1 1/1 1/1 0/1 0/1 1/1 1/1 1/1
§exists on Collator prototype No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§NumberFormat MDN (Mozilla Development Network) logo  0/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 4/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 0/5 5/5 5/5 0/5 0/5 4/5 5/5 5/5
§exists on intl object No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§exists on intl object No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§creates new NumberFormat instances No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§constructor called without new creates instances No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§accepts valid language tags No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes
§DateTimeFormat MDN (Mozilla Development Network) logo  0/6 0/6 0/6 4/6 4/6 4/6 6/6 6/6 6/6 6/6 4/6 4/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 5/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 0/6 6/6 6/6 0/6 0/6 5/6 6/6 6/6
§exists on intl object No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§creates new DateTimeFormat instances No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§constructor called without new creates instances No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§accepts valid language tags No No No Yes Yes Yes Yes Yes Yes Yes Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes[4] Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes
§resolvedOptions().timeZone defaults to the host environment No No No No No No Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes ? Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes ? No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§accepts IANA timezone names No No No No No No Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes Yes
§String.prototype.localeCompare MDN (Mozilla Development Network) logo  0/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1
§exists on String prototype No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Number.prototype.toLocaleString MDN (Mozilla Development Network) logo  0/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1
§exists on Number prototype No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Array.prototype.toLocaleString MDN (Mozilla Development Network) logo  0/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1
§exists on Array prototype No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Object.prototype.toLocaleString MDN (Mozilla Development Network) logo  0/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1
§exists on Object prototype No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Date.prototype.toLocaleString MDN (Mozilla Development Network) logo  0/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1
§exists on Date prototype No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Date.prototype.toLocaleDateString MDN (Mozilla Development Network) logo  0/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1
§exists on Date prototype No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Date.prototype.toLocaleTimeString MDN (Mozilla Development Network) logo  0/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1
§exists on Date prototype No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes

[1] Flagged features have to be enabled via "Experimental Javascript features" flag unless otherwise stated

[2] Flagged features have to be enabled via --harmony flag

[3] Flagged features have to be enabled via --harmony or --es_staging flag

[4] The feature is available on desktop versions only, it is not available on mobile versions.