JS Array method summarizes the addition and deletion of array elements

JS array element Additions and deletions have not been well organized, today see good text together, PS in the JSON format of the operation is the same kind of
var arr = new Array ();
Arr[0] = "AAA";
ARR[1] = "BBB";
ARR[2] = "CCC";
alert (arr.length);//3
Arr.pop ();
alert (arr.length);//2
Alert (arr[arr.length-1]);//bbb
Arr.pop ();
Alert (arr[arr.length-1]);//aaa
alert (arr.length);//1

var arr2 = new Array ();
alert (arr2.length);//0
Arr2[0] = "AAA";
ARR2[1] = "BBB";
alert (arr2.length);//2
Arr2.pop ();
alert (arr2.length);//1
ARR2 = Arr2.slice (0,arr2.length-1);
alert (arr2.length);//0
Arr2[0] = "AAA";
ARR2[1] = "BBB";
ARR2[2] = "CCC";
ARR2 = Arr2.slice (0,1);
alert (arr2.length);//1
Alert (arr2[0]);//aaa
Alert (arr2[1]);//undefined

Shift: Deletes the first item of the original array and returns the value of the deleted element; returns undefined if the array is empty
var a = [1,2,3,4,5];
var B = A.shift (); a:[2,3,4,5] B:1

unshift: Adds a parameter to the beginning of the original array and returns the length of the array
var a = [1,2,3,4,5];
var B = A.unshift ( -2,-1); a:[-2,-1,1,2,3,4,5] B:7
Note: The test return value under IE6.0 is always undefined,ff2.0 Test return value is 7, so the return value of this method is not reliable, need to use the return value when the splice can be used instead of this method.

pop: Deletes the last item of the original array and returns the value of the deleted element; returns undefined if the array is empty
var a = [1,2,3,4,5];
var B = A.pop (); a:[1,2,3,4] B:5//Do not return the words directly to call on it.

push: Adds a parameter to the end of the original array and returns the length of the array
var a = [1,2,3,4,5];
var B = A.push (6,7); a:[1,2,3,4,5,6,7] B:7

concat: Returns a new array that consists of adding parameters to the original array
var a = [1,2,3,4,5];
var B = A.concat (6,7); a:[1,2,3,4,5] b:[1,2,3,4,5,6,7]

Splice (Start,deletecount,val1,val2,...) : Deletes the DeleteCount entry starting from the start position and inserts the Val1,val2 from that position,...
var a = [1,2,3,4,5];
var B = A.splice (2,2,7,8,9); a:[1,2,7,8,9,5] b:[3,4]
var B = a.splice (0,1); With shift
A.splice (0,0,-2,-1); var B = a.length; With Unshift
var B = A.splice (a.length-1,1); With pop
A.splice (a.length,0,6,7); var B = a.length; With push

Reverse: Reverse the array
var a = [1,2,3,4,5];
var B = A.reverse (); a:[5,4,3,2,1] b:[5,4,3,2,1]

sort (orderfunction): Sorts the array by the specified parameters
var a = [1,2,3,4,5];
var B = A.sort (); a:[1,2,3,4,5] b:[1,2,3,4,5]

Slice (start,end): Returns a new array that consists of the entries from the original array that specify the starting subscript to the end subscript
var a = [1,2,3,4,5];
var B = a.slice (2,5); a:[1,2,3,4,5] b:[3,4,5]

Join (Separator): Sets the element group of the array as a string,Use separator as the delimiter, and omit by default with commas
var a = [1,2,3,4,5];
var B = A.join ("|"); a:[1,2,3,4,5] B: "1|2|3|4|5"

Another way to manipulate strings using the array emulation Javastringbuffer:

/**
* String processing function
*/
function StringBuffer ()
{
var arr = new Array;
This.append = function (str)
{
Arr[arr.length] = str;
};

this.tostring = function ()
{
Return arr.join (""); Ping the append incoming array into a string
};
}

In the application today, it is suddenly found that join is a good way to convert an array into a string, so it is encapsulated into objects using:

/**
* convert an array into a string of specific symbol splits
*/
function arraytostring (arr,separator)
{
if (!separator) separator = "";//separator is null default is NULL
return Arr.join (separator);
}

/**
* Find the string contained in the array
*/
function arrayfindstring (arr,string)
{
var str = arr.join ("");
return Str.indexof (String);
}

JS Array method summarizes the addition and deletion of array elements