let

Declares a variable with block level scope

Spec	https://tc39.es/ecma262/#sec-let-and-const-declarations
Status	Other

IE	Edge	Firefox	Chrome	Safari	Opera
			98
		95	97
		94	96	TP
11 ⁽⁵⁾	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 ⁽⁴⁾	71
	85	83	85	10 ⁽⁴⁾	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 ⁽³⁾
		49	50		34 ⁽³⁾
		48	49		33 ⁽³⁾
		47	48 ⁽³⁾		32 ⁽³⁾
		46	47 ⁽³⁾		31 ⁽³⁾
		45	46 ⁽³⁾		30 ⁽³⁾
		44	45 ⁽³⁾		29 ⁽³⁾
		43 ⁽¹⁾	44 ⁽³⁾		28 ⁽³⁾
		42 ⁽¹⁾	43 ⁽³⁾		27 ⁽²⁾
		41 ⁽¹⁾	42 ⁽³⁾		26 ⁽²⁾
		40 ⁽¹⁾	41 ⁽³⁾		25 ⁽²⁾
		39 ⁽¹⁾	40 ⁽²⁾		24 ⁽²⁾
		38 ⁽¹⁾	39 ⁽²⁾		23 ⁽²⁾
		37 ⁽¹⁾	38 ⁽²⁾		22 ⁽²⁾
		36 ⁽¹⁾	37 ⁽²⁾		21 ⁽²⁾
		35 ⁽¹⁾	36 ⁽²⁾		20 ⁽²⁾
		34 ⁽¹⁾	35 ⁽²⁾		19 ⁽²⁾
		33 ⁽¹⁾	34 ⁽²⁾		18 ⁽²⁾
		32 ⁽¹⁾	33 ⁽²⁾		17 ⁽²⁾
		31 ⁽¹⁾	32 ⁽²⁾		16 ⁽²⁾
		30 ⁽¹⁾	31 ⁽²⁾		15 ⁽²⁾
		29 ⁽¹⁾	30 ⁽²⁾		12.1
		28 ⁽¹⁾	29 ⁽²⁾		12
		27 ⁽¹⁾	28 ⁽²⁾		11.6
		26 ⁽¹⁾	27 ⁽²⁾		11.5
		25 ⁽¹⁾	26 ⁽²⁾		11.1
		24 ⁽¹⁾	25 ⁽²⁾		11
		23 ⁽¹⁾	24 ⁽²⁾		10.6
		22 ⁽¹⁾	23 ⁽²⁾		10.5
		21 ⁽¹⁾	22 ⁽²⁾		10.0-10.1
		20 ⁽¹⁾	21 ⁽²⁾		9.5-9.6
		19 ⁽¹⁾	20 ⁽²⁾		9
		18 ⁽¹⁾	19 ⁽²⁾
		17 ⁽¹⁾	18
		16 ⁽¹⁾	17
		15 ⁽¹⁾	16
		14 ⁽¹⁾	15
		13 ⁽¹⁾	14
		12 ⁽¹⁾	13
		11 ⁽¹⁾	12
		10 ⁽¹⁾	11
		9 ⁽¹⁾	10
		8 ⁽¹⁾	9
		7 ⁽¹⁾	8
		6 ⁽¹⁾	7
		5 ⁽¹⁾	6
		4 ⁽¹⁾	5
		3.6 ⁽¹⁾	4
		3.5 ⁽¹⁾
		3 ⁽¹⁾
		2 ⁽¹⁾

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 ⁽³⁾	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⁾									4 ⁽³⁾
10.0-10.2 ⁽⁴⁾
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

Supports a non-standard version that can only be used in script elements with a type attribute of application/javascript;version=1.7. As other browsers do not support these types of script tags this makes support useless for cross-browser support.
Requires the ‘Experimental JavaScript features’ flag to be enabled
Only supported in strict mode
let bindings in for loops are incorrectly treated as function-scoped instead of block scoped.
let variables are not bound separately to each iteration of for loops

Resources

Data by caniuse.com
Licensed under the Creative Commons Attribution License v4.0.
https://caniuse.com/let