Web Storage - name/value pairs

Method of storing data locally like cookies, but for larger amounts of data (sessionStorage and localStorage, used to fall under HTML5).

Spec	https://html.spec.whatwg.org/multipage/webstorage.html#storage
Status	WHATWG Living Standard

IE	Edge	Firefox	Chrome	Safari	Opera
			98
		95	97
		94	96	TP
11	95	93	95	15	80
10	94	92	94	14.1	79
9	93	91	93	14	78
8	92	90	92	13.1	77
Show all
7	91	89	91	13	76
6	90	88	90	12.1	75
5.5	89	87	89	12	74
	88	86	88	11.1	73
	87	85	87	11	72
	86	84	86	10.1	71
	85	83	85	10	70
	84	82	84	9.1	69
	83	81	83	9	68
	81	80	81	8	67
	80	79	80	7.1	66
	79	78	79	7	65
	18	77	78	6.1	64
	17	76	77	6	63
	16	75	76	5.1	62
	15	74	75	5	60
	14	73	74	4	58
	13	72	73	3.2	57
	12	71	72	3.1	56
		70	71		55
		69	70		54
		68	69		53
		67	68		52
		66	67		51
		65	66		50
		64	65		49
		63	64		48
		62	63		47
		61	62		46
		60	61		45
		59	60		44
		58	59		43
		57	58		42
		56	57		41
		55	56		40
		54	55		39
		53	54		38
		52	53		37
		51	52		36
		50	51		35
		49	50		34
		48	49		33
		47	48		32
		46	47		31
		45	46		30
		44	45		29
		43	44		28
		42	43		27
		41	42		26
		40	41		25
		39	40		24
		38	39		23
		37	38		22
		36	37		21
		35	36		20
		34	35		19
		33	34		18
		32	33		17
		31	32		16
		30	31		15
		29	30		12.1
		28	29		12
		27	28		11.6
		26	27		11.5
		25	26		11.1
		24	25		11
		23	24		10.6
		22	23		10.5
		21	22		10.0-10.1
		20	21		9.5-9.6
		19	20		9
		18	19
		17	18
		16	17
		15	16
		14	15
		13	14
		12	13
		11	12
		10	11
		9	10
		8	9
		7	8
		6	7
		5	6
		4	5
		3.6	4
		3.5
		3
		2

Safari on iOS	Opera Mini	Android Browser	Blackberry Browser	Opera Mobile	Android Chrome	Android Firefox	IE Mobile	Android UC Browser	Samsung Internet	QQ Browser	Baidu Browser	KaiOS Browser
15	all	94	10	64	94	92	11	12.12	15.0	10.4	7.12	2.5
14.5-14.8		4.4.3-4.4.4	7	12.1			10		14.0
14.0-14.4		4.4		12					13.0
13.4-13.7		4.2-4.3		11.5					12.0
Show all
13.3		4.1		11.1					11.1-11.2
13.2		4		11					10.1
13.0-13.1		3		10					9.2
12.2-12.5		2.3							8.2
12.0-12.1		2.2							7.2-7.4
11.3-11.4		2.1							6.2-6.4
11.0-11.2									5.0-5.4
10.3									4
10.0-10.2
9.3
9.0-9.2
8.1-8.4
8
7.0-7.1
6.0-6.1
5.0-5.1
4.2-4.3
4.0-4.1
3.2

Notes

Bugs

• IE 8 and 9 store data based only on hostname, ignoring the scheme (http vs https) and port number as required by the specification.

• In iOS 5 & 6 localStorage data is stored in a location that may occasionally be cleared out by the OS.

• In private browsing mode, Safari and iOS Safari up to including version 10.x as well as the Android browser (not include Chrome for Android) do not support setting sessionStorage or localStorage.

• In IE attempting to access localStorage on HTML files served from the file system results in the localStorage object being undefined

• Internet Explorer does not support storing most of the ASCII characters with codes under x20.

• The "storage" event is completely wrong in IE:
  IE10 : The storage event is fired even on the originating document where it occurred. Causes problems with multiple windows websites, and huge problems with iframes.
  IE11 : The storage event's oldValue and newValue are identical (newValue is supposed to contain the storage's updated value).

  Partial workaround: regularly probe the storage's value and compare with the last known value on all pages where you want to listen to this event, and track the last submitted value to determine if the modification was triggered locally.

• IE10 in Windows 8 has an issue where localStorage can fail with the error message "SCRIPT5: Access is denied" if "integrity" settings are not set correctly. see details

• Storing large amounts of data in Safari (on OSX & iOS) can result in freezing the browser see bug

• IE11 does not properly synchronize localStorage between different windows. see bug

Resources

• MDN Web Docs - Web Storage
• Support library
• Simple demo
• has.js test
• WebPlatform Docs