Simple Array application

I. Definition of Arrays
There are three methods to define arrays in javascript:
1. The number of arrays is defined as: var arr = [1, 2, 3];
2. Use constructors to define them, for example, VAR arr1 = new array ();
3. Use other variables to define an array
In the defined array, VAR arr = [1, 2, 3] is equivalent to VaR arr = new array (1, 2, 3),

VaR arr = [3] and VAR arr = new array (3) are not equivalent. The latter refers to the length.

Element
Ii. Array application
1. Split the string into an array using the split () method.
<Script language = "JavaScript">
VaR STR = "Monday, Tuesday, Wednesday, Thursday, Saturday, Sunday ";
VaR arr = Str. Split (",");
Document. Write (ARR. tostring ());
</SCRIPT>
2. Use of array elements. arrays use array subscript to index array elements (in

In JavaScript, a comma is equivalent to a plus sign)
3. Add array elements
VaR myarr = new array (100, true, "string"); // there are only three elements, so the most

The size is marked as 2
Arrelement (myarr );
Myarr [3] = true; // Add an element
Arrelement (myarr );
4. Multi-dimensional arrays cannot be defined in Javascript. You can use this method to define multi-dimensional arrays.
<Script language = "JavaScript">
VaR myarr1 = new array (1, 2, 3 );
VaR myarr2 = new array ("string 1", "string 2", "string 3 ");
VaR myarr3 = new array (true, false, true );
VaR myarr = new array (myarr1, myarr2, myarr3 );
Document. Write (myarr [0] [0], "<br>"); // result 1: Understanding is equivalent to myarr [0]

The first array is myarr1, and myarr [0] [0] is equivalent to myarr1 [0], which is the first of myarr1.

Elements
Document. Write (myarr [1] [2], "<br>"); // The result is string 3.
Document. Write (myarr [2] [1], "<br>"); // The result is: false.
</SCRIPT>
5. Convert the array into a string
VaR myarr = new array (100, true, "string ");
Document. Write (myarr. tolocalestring ());
Document. Write (myarr. Join ("-"); // join cannot be converted to a local string.
6. add elements to the array, delete the elements of the array, and replace the elements of the array.
Array. unshift (1); // It is added to the front of the array element, that is, the header of the array.
Array. Push (1); // On the contrary, the array element is added to the end of the array.
Array. splice (1, 0, "this"); // Add an array element.

Any location <note that the second parameter is 0>
Array. Concat (2); // Add an array element or add it to the end of the array element

New array, will not affect the array itself
Delete elements in the array header: array. Shift ();
Delete the specified element: the position of the array. splice () // element, the specified length
Replace the specified element: array. splice (, "this"); // The Position of the element is the subscript, element

Is a string, the replacement string