Today I learned a string object, an array object, a Date object.
String object:
Create a String object: The first: A string variable defined with single and double quotes then it is a string object
var variable name = "string"
The second type: Use the New keyword and the string () method to create
var variable name =new srting ()
Property: Stringobject (String object). Length Gets the total number of characters in the string!
Method: Stringobject.charat (Index) returns a specified subscript character; index: represents the specified subscript
Stringobject.indexof (substr) finds the position of the first occurrence of the string, and returns its corresponding subscript if found;
Returns 1 if the lookup is a "word" found in case the return is
The subscript of the first letter of the word; substr: the string to find
stringobject.substring) (Startindex[endindex]): Intercepts substrings from the original string; Statindex: Indicates the start of intercept subscript;
EndIndex: Optional If no write indicates that the original character has been intercepted from the beginning subscript
At the end of the string, if there is a write, the end of the subscript if you want to use the second parameter
Count so be sure to remember
Stringobject.substr (Startindex[,length]) intercepts the substring from the original string; StartIndex: Indicates the start of intercept subscript; length: Optional If no write indicates that the end of the original string is truncated from the beginning of the subscript, if there is a write The table
Length of the truncated string
Stringobject.substring (Startindex[,endindex]) intercepts substrings from the original string; StartIndex: Indicates the start of intercept subscript; EndIndex: Optional If not written Represents the end of the original string from the beginning of the subscript;
Write indicates the end of the subscript; If you want to use the second parameter then be sure to add 1.
Stringobject.tolowercase () converts uppercase letters to lowercase
Stringobject.touppercase () converts lowercase letters to uppercase
Stringobject.split (Sep) divides a string into an array; Sep: represents the specified delimiter
Stringobject.replace (regular expression, character to replace) replace one string with another
Stringobject.localecompare (target) compares the order of two strings
Array object:
The first method: use [] to create an array
The second method: Use the New keyword and the array () method to create
Property:Arrayobject.length Gets the length of the array
Method:Arrayobject.shift () deletes the first element in the array and returns it
Arrayobject.push () adds one or more array elements to the end of the array and returns the new length
arrayobject.join ([Sep]) merges an array into a string; Sep: Optional If this parameter is not filled in, it means to connect using the comma below the English language, and If there is a write, it is represented by the specified symbol Come in
Row connection
Arrayobject.reverse () flips the array
Arrayobject.sort (sortby) sorting an array element
! If the method is called without parameters, the elements in the array are sorted alphabetically, more precisely, by the order in which the characters are encoded. To do this, you should first convert the elements of the array to a string, if necessary, for comparison.
! If you want to sort by other criteria, you need to provide a comparison function that compares two values and returns a number that describes the relative order of the two values. The comparison function should have two parameters A and B with the following return values:
If a is less than B, a value that is less than 0 is returned if a should appear before B in the sorted array. If a equals B, 0 is returned. If a is greater than B, a value greater than 0 is returned.
Date object:
Create a Date object:
First: Use the new keyword with date () to create a parameter
Second: Use the new keyword with date () to create without parameters
Dateobject.getfullyear (): Get a 4-digit year
Dateobject.getmonth (): Get month Value: 0-11 0 means January 11 means December
Dateobject.getdate (): Gets the number of days to value: 1-31
Dateobject.gethours (): Gets the hour value: 0~23
Dateobject.getminutes (): Gets the minute value: 0~59
Dateobject.getseconds (): Gets the number of seconds to value: 0~59
Dateobject.getmilliseconds (): Gets the number of milliseconds to value: 0~999
Dateobject.getday (): Gets the value of one day of the week: 0-6 0 = Sunday
Dateobject.gettime (): Gets the time stamp obtained is from January 1, 1970 to present the millisecond number of GMT
Summary 11th Day