# JS Common functions

Source: Internet
Author: User

Arithmetic operations in JS

`1Math.pow (2,53)//= 9.,007,199,254,740,99e,+15:2 of 53 power2Math.Round (. 6)//= 1.0: Rounding3Math.ceil (. 6)//+ 1.0: Rounding up4Math.floor (. 6)//+ 0.0: Rounding down5Math.Abs (-5)//= 5: Absolute value6Math.max (x, Y, z)//returns the maximum value7Math.min (x, Y, z)//returns the minimum value8Math.random ()//generates a pseudo-random number greater than or equal to 0 less than 1.09Math.PI//π: PiTenMath.e//e: base of natural logarithm OneMATH.SQRT (3)//square root of 3 AMath.pow (3, 1/3)//Cubic root of 3 -Math.sin (0)//Trigonometric Functions: Math.Cos, Math.atan, etc. -Math.log (10)//Natural logarithm of 10 theMath.log (+)/MATH.LN10//logarithm with base 100 of 10 -Math.log (/MATH.LN2)//logarithm with base 512 of 2 -Math.exp (3)//three power of e`

JS Date and Time

`1 varthen =NewDate (2011, 0, 1);//January 1, 20112 varlater =NewDate (2011, 0, 1, 17, 10, 30);//the same day, local time 5:10:30pm,3 varnow =NewDate ();//Current date and time4 varelapsed = Now-then;//Date Subtraction: Calculates the number of milliseconds in a time interval5Later.getfullyear ()// +/-6Later.getmonth ()//+ 0: Month counting starting from 07Later.getdate ()//+ 1: Number of days to count starting from 18Later.getday ()//= 5: Get day of the week, 0 for Sunday, 5 for Monday9Later.gethours ()//= = local time 17:5pmTenLater.getutchours ()//use UTC to denote hours, based on time zone`

JS string processing

`1 vars = "Hello, world"//Define a string2S.charat (0)//= "h": first character3S.charat (s.length-1)//= "D": Last character4S.substring (1,4)//= "ell": 2nd to 4th character5S.slice (1,4)//= "ell": Ibid .6S.slice (-3)//= "Rld": last three characters7S.indexof ("L")//+ 2: Position of the first occurrence of the character L8S.lastindexof ("L")//= 10: The last occurrence of the character L9S.indexof ("L", 3)//+ 3: The position of the first occurrence of the character L at position 3 and afterTenS.split (",")//= = ["Hello", "World"] split into substrings OneS.replace ("H", "H")//= = "Hello, world": Full character substitution AS.touppercase ()`

JS Common functions

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